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__index_level_0__
int64
41
229k
664066
A plane flying with a constant speed of {eq}\rm 24\ km/min {/eq} passes over a ground radar station at an altitude of {eq}\rm 9 \ km {/eq} and climbs at an angle of {eq}40 ^\circ {/eq}. At what rate is the distance from the plane to the radar station increasing {eq}3 {/eq} minutes later?
23.91 km/min
Float
Physics
Senior High School
223,299
284802
A semicircular plate with radius {eq}\displaystyle 10\ m {/eq} is submerged vertically in water so that the top is {eq}2\ m {/eq} above the surface. Express the hydrostatic force against one side of the plate as an integral and evaluate it. (Round your answer to the nearest whole number. Use {eq}\displaystyle 9.8\ \f...
3841000 N
Integer
Physics
University
33,160
1432275
A block of mass 2.50 kg is pushed 3.00 m along a frictionless horizontal table by a constant applied force of magnitude 18.0 N directed at an angle of 25.0 degrees below the horizontal. Determine the work done by the net force on the block.
50.0 J
Float
Physics
Senior High School
93,044
647755
An ideal gas is contained in a cylinder with a volume of {eq}5.0 \times 10^2 \ mL {/eq} at a temperature of {eq}30.0^\circ \ C {/eq} and a pressure of {eq}710.0 \ torr {/eq}. The gas is then compressed to a volume of {eq}27 \ mL {/eq}, and the temperature is raised to {eq}800.0 ^\circ \ C {/eq}. What is the...
61.56 atm
Float
Physics
Senior High School
59,020
1249741
An electron has an uncertainty in its position of 639 pm. What is the uncertainty in its velocity? Express your answer with the appropriate units.
9.07e+04 m/s
Float
Physics
Senior High School
217,639
1997324
To focus a camera on objects at different distances, the converging lens is moved toward or away from the image sensor, so a sharp image always falls on the sensor. A camera with a telephoto lens (f = 100 mm) is to be focused on an object located first at a distance of 3.5 m and then at 50.0 m. Over what distance must ...
0.0028 m
Float
Physics
Senior High School
157,747
1165493
An object with a mass of #90 g# is dropped into #500 mL# of water at #0^@C#. If the object cools by #30 ^@C# and the water warms by #30 ^@C#, what is the specific heat of the material that the object is made of?
23.3kJkg^-1K^-1
Float
Physics
Senior High School
43,871
1888922
The time period of earth taken as {eq}T {/eq} and its distance from sun {eq}R {/eq}. What will be the distance of a certain planet from sun whose time period is {eq}64 {/eq} times that of earth ?
16R
Expression
Physics
Senior High School
47,553
1049940
A {eq}60\ cm^3 {/eq} block of iron is removed from an {eq}800 ^\circ C {/eq} furnace and immediately dropped into {eq}200\ mL {/eq} of {eq}20 ^\circ C {/eq} water. What percentage of the water boils away?
18.1%
Percentage
Physics
Senior High School
216,314
1993387
Air is compressed steadily by a reversible compressor from an inlet state of 100 kPa and 300 K to an exit pressure of 900 kPa. Determine the compressor work for a two-stage compression from 100-300 kPa and 300-900kPa, with intercooling with an isentropic efficiency for both compressors.
222.34 kJ/kg
Float
Physics
University
91,167
322855
Monochromatic light shines through a diffraction grating with 440 lines/mm, then onto a screen 3 m away. If the 2nd order bright spot is 1.2 m from the center of the pattern, what wavelength was used?
422 nm
Float
Physics
Senior High School
187,090
1538881
If two tiny identical spheres attract each other with a force of 3.0 nN when they are 25 cm apart, what is the mass of each sphere?
1.68 kg
Float
Physics
Senior High School
55,703
430713
A daredevil attempts to swing from the roof of a {eq}24 \, \mathrm{m} {/eq} high building to the bottom of an identical building using a {eq}24 \, \mathrm{m} {/eq} rope. He starts from rest with the rope horizontal, but the rope will break if the tension force in it is twice the weight of the daredevil. How high is t...
8 m
Integer
Physics
Senior High School
215,084
653432
Two non-conducting shells are fixed in place. Shell 1 has a surface charge density of .0000071 C/m{eq}^{2} {/eq} and a radius of 4.7 cm. Shell 2 has a charge density of .0000067 and a radius of 2.5 cm. The shell centers are separated by a length of 11.7 cm. What is the net electric field at x = 2.3 cm?
5.3e+4 N/C
Float
Physics
University
22,451
687993
How do you solve this force equilibrium equation for x? Point charge {eq}q_1 {/eq} has a magnitude of {eq}1 \times 10^{-6} C {/eq}, {eq}q_2 {/eq} has magnitude {eq}2 \times 10^{-6} C {/eq}, and d = 2.0 m. x is the distance between {eq}q_1 {/eq} and a 3rd point charge {eq}q_3 {/eq}. Find the distance x at which th...
x ≈ 0.828 m, assuming the same polarity x ≈ 4.828 m, assuming opposite polarities
List
Physics
Senior High School
187,154
1183635
Brittany is changing the tire of her car on a steep hill 20.0 m high. She trips and drops the 10.0 kg spare tire, which rolls down the hill with an initial speed of 2.00 m{eq}/ {/eq}s and then rolls to the next hill which is 5 m high. What is the speed of the tire at the top of the 5.00 m high hill?
17.27 m/s
Float
Physics
Senior High School
214,555
1502543
An automobile tire contains air at 225 103 Pa at 298 K. The stem valve is removed and the air is allowed to expand adiabatically against the constant external pressure of 1.00 105 Pa until P = P (external). For air, CV,m = 5/2 R. Assume ideal gas behavior. Calculate the final temperature.
250.72K
Float
Physics
University
58,241
1159268
The electromagnetic wave that delivers a cellular phone call to a car has a magnetic field with an rms value of {eq}\rm 1.20 \times 10^{-10} \ T {/eq}. The wave passes perpendicularly through an open window, the area of which is {eq}\rm 0.20 \ m^2 {/eq}. How much energy does this wave carry through the window during ...
2.06e-5 J
Float
Physics
University
156,388
1002235
A {eq}+90\ nC {/eq} charge is positioned {eq}1.7\ m {/eq} from a {eq}+52\ nC {/eq} charge. What is the magnitude of the electric field at the midpoint of these charges, in units of {eq}N/C {/eq}?
473.35 N/C
Float
Physics
Senior High School
132,538
76022
The 1994 Winter Olympics included the aerials competition in skiing. In this event skiers speed down a ramp that slopes sharply upward at the end. The sharp upward slope launches them into the air, where they perform acrobatic maneuvers. In the women's competition, the end of a typical launch ramp is directed 63 degree...
18.3 m/s
Float
Physics
Senior High School
212,575
1265192
Two identical balls each having density {eq}\rho {/eq} are suspended from a common point by two insulating strings of equal length. Both the balls have equal mass and charge. In equilibrium, each string makes an angle {eq}\theta {/eq} with vertical. Now both the balls are immersed in liquid. As a result, the angle do...
ρ/(ρ-σ)
Fraction
Physics
Senior High School
214,082
1648825
A particle with charge -7 {eq}\mu{/eq}C is located on the x-axis at the point 10 cm , and a second particle with charge 8 {eq}\mu{/eq}C is placed on the x-axis at 8 cm. What is the magnitude of the total electrostatic force on a third particle with charge 4 {eq}\mu{/eq}C placed on the x-axis at 2 cm ? The Coulomb co...
40.53 N
Float
Physics
Senior High School
98,668
1709840
The conductance of a wire 20 m long and 3 mm in diameter is 0.54 mho. If a wire of the same material has length 50 mm and diameter 5 mm, what is its conductance?
600 mho
Integer
Physics
Senior High School
221,126
1192797
A vehicle traveling with constant acceleration from A to B in a straight line AB has velocities u and v at A and B respectively. C is the midpoint of AB. If the time taken to travel from A to C is twice the time to travel from C to B, then what is the velocity v of the vehicle at B?
v = 7u
Expression
Physics
Senior High School
120,982
1668812
A capacitor is connected to a 16 kHz oscillator that produces an rms voltage of 7.0 V. The peak current is 70 mA. What is the value of the capacitance C?
70 nF
Float
Physics
Senior High School
136,726
677724
A system gains {eq}\displaystyle 3330 J {/eq} of heat at a constant pressure of {eq}\displaystyle 1.46 \times 10^5 Pa, {/eq} and its internal energy increases by {eq}\displaystyle 4190 J. {/eq} What is the change in the volume of the system, and is it an increase or a decrease? {eq}\displaystyle \Delta V = \bo...
-5.89e-3 m^3. The change in the volume of the system decreases
Float
Physics
Senior High School
81,410
850333
A horizontal wire carries a current {eq}I_1 = 80 A {/eq} dc. A second parallel wire 20 cm below it must carry how much current, {eq}I_2 {/eq}, so that it doesn't fall due to gravity? The lower wire has a mass of 0.12 g per meter of length.
15 A
Integer
Physics
University
178,036
1816747
A 500 g glass beaker is in thermal equilibrium with 100 ml of 20{eq}^\circ {/eq}C water in it. If a 5 g sample of copper is placed into the water and the system is allowed to come into thermal equilibrium, what will the final temperature of the system be? (Assume there is no heat loss to the air)
20.18^°C
Float
Physics
Senior High School
198,201
1553069
An electron inside a hydrogen atom is confined to within a space of about 0.110 nm. If the electron mass is 9.11 x {eq}10^{-31} {/eq} kg, what is the uncertainty in the electron's velocity? a) 1.05 x {eq}10^6 {/eq} m/s b) 1.50 x {eq}10^6 {/eq} m/s c) 1.05 x {eq}10^8 {/eq} m/s d) 1.50 x {eq}10^8 {/eq} m/s
a
Multiple Choice
Physics
University
28,756
282765
The half-life of radium-226 is 1590 years. If a sample contains 400mg, how many mg will remain after 1000 years?
257 mg
Float
Physics
Senior High School
170,467
1567101
Two charged balls, one with a charge of +5.0 {eq}\mu {/eq}C and the of +2.4 {eq}\mu {/eq}C, are placed a distance d = 10.0 cm apart from each other and rigidly held in place. A third ball with a charge of -3.0 {eq}\mu {/eq}C is dangled from a string between the two charged balls such that it remains in equilibrium. ...
4.092 cm
Float
Physics
Senior High School
155,480
783982
A very small disc winds around a larger circular disc of radius $R$. It is connected to it by a string of length l that remains tight. What distance does it travel before it hits the larger disc of radius $R$ ? I've estimated that it is $2\pi(l-R)$ based on assuming a spiral is a little like a series of concentric circ...
L^2 / (2R)
Expression
Physics
University
228,029
762688
You push a wagon of mass M = 10.2 kg up a hill of angle {eq}\theta {/eq} = 11.8 degrees and height h = 3.5 m. You push with a constant force equal to 1/3 the force of gravity on the wagon. Your push is directly up the hill. If the wagon starts at rest at the bottom of the hill, what is its kinetic energy at the top o...
221
Integer
Physics
Senior High School
216,926
1157365
A 533-N person stands on a uniform board of weight 113 N and length 8.3 m. The board is supported at each end. If the support force on the right edge is three times that at the left end, how far from the right end is the person?
6.51 m
Float
Physics
Senior High School
77,901
1211385
The rectangular loop shown below is located in a uniform magnetic field of {eq}0.10 T {/eq} pointing in the positive y direction. {eq}A = 6.5 cm {/eq}; {eq}B = 8.0 cm {/eq}; {eq}\theta = 30.0^{\circ} {/eq} ; {eq}I = 8.0 A {/eq}. Calculate the magnitude of the torque on the loop.
3.6e-3 N.m
Float
Physics
Senior High School
183,294
1380651
Four-point charges have the same magnitude of {eq}2.18 \times 10^{-12} {/eq} C and are fixed to the corners of a square that is 3.95 cm on aside. Three of the charges are positive and one is negative. Determine the magnitude of the net electric field that exists at the center of this square?
50.28 N/C
Float
Physics
University
172,443
1814963
A beam of UV light with a wavelength of 94 nm was directed through a container filled with a noble gas. As a result, some of the gas atoms were ionized and the ejected electrons were found to have a speed of 6.11 x 10{eq}^5 {/eq} m s{eq}^{-1} {/eq}. Calculate the energy required to ionize an atom of this gas.
1.9e-18 J
Float
Physics
Senior High School
150,895
102158
A glass vessel is filled with exactly 840 mL of turpentine at {eq}\rm 25.8 ^\circ C {/eq}. What volume of liquid will overflow if the temperature is raised to {eq}\rm 75.9 ^\circ C {/eq}? Take {eq}\rm \beta_{glass} = 9.9 \times 10^{-6}\ (^\circ C)^{-1} {/eq} Take {eq}\rm \beta_{turpentine} = 9.4 \times 10^{-4}...
39e-6 m^3
Float
Physics
Senior High School
122,542
244348
A wheel spins on a horizontal axis, with an angular speed of 140rad/s and with its angular velocity pointing east. Determine the magnitude of the angular velocity after an angular acceleration of 35 rad/s^2, pointing 68 degrees west of north, with a time of 4.6 seconds.
61.015 rad/s
Float
Physics
University
164,577
1149105
A basketball (of mass {eq}m {/eq}) is dropped from rest from a height of {eq}h_1 {/eq}, onto a bathroom scales. As it bounces, its contact with the scales lasts for a time interval {eq}\Delta t {/eq}. The ball bounces up to a height of {eq}h_2 {/eq}. Find the average reading of the scales when the ball was in conta...
F = \frac{m(\sqrt{2gh_2} + \sqrt{2gh_1})}{\Delta t}
Expression
Physics
Senior High School
40,792
307905
If an astronaut can throw a certain wrench 10.0 m vertically upward on earth, how high could he throw it on our moon if he gives it the same starting speed in both places?
58.8 meters
Float
Physics
Senior High School
197,882
722216
Determine the change in energy when an electron transitions from n= to n=5?
13.056 ev
Float
Physics
University
48,378
1734961
Point charge {eq}\rm 3.0 \ \mu C {/eq} is located at x = 0, y = 0.30 m. Another point charge {eq}\rm -3.0 \ \mu C {/eq} is located at x = 0 y = -0.30 m. What are the magnitude and direction of the total electric force that these charges exert on a third point charge {eq}\rm 5.0 \ \mu C {/eq} at x = 0.40 m, y = 0?
0.647 N j
Expression
Physics
University
20,827
738061
A square loop is rotating in the plane of the page around an axis through its center. A uniform magnetic field is directed into the page. What is the direction of the induced current in the loop? a. clockwise b. counterclockwise c. no induced current d. unable to determine
c
Multiple Choice
Physics
Senior High School
166,924
879471
Pitcher claims he can throw a 0.153 kg baseball with as much momentum as a 2.0 g bullet moving with a speed of {eq}1.50 \times 10^3 \; m/s {/eq}. What must the baseball's speed be if the pitcher's claim is valid?
20 m/s
Integer
Physics
Senior High School
168,531
462659
A mass of 6.482 kg of saturated water vapor at 400 kPa is heated at constant pressure in a piston cylinder device until the temperature reaches 200{eq}\displaystyle ^oC. {/eq} Calculate the work done by the steam during this process.
186.559 kJ
Float
Physics
University
177,310
1298144
What are the forces acting on a racing car while it slows down around a turn?
The forces acting on a racing car as it slows down around a turn include friction, the applied force, gravity, and the normal force.
List
Physics
Senior High School
197,765
443296
1. An equation that governs the radial displacement u (measured in length units) from a center line at a distance r gives the Euler-Cauchy equation for the function u(r) is {eq}\frac{d^2u}{dr^2} + \frac{1}{r} \frac{du}{dr} - \frac{1}{r^2} u = 0 {/eq} Determine the units of each of the quantities in this equation.
1/length
String
Physics
University
55,420
1554532
A piston-cylinder device with stops initially contains 0.3 kg of steam at 1 MPa and 400°C. When the piston is on the stops the cylinder volume is 60% of the initial volume. Determine the heat removed and draw a T-v diagram if the final state has pressure of 500 kPa.
-477.65 kJ
Float
Physics
University
2,420
2030139
A stationary bomb of 10 kg mass explodes into 3 fragments. Two of these parts, having mass 4 kg and 2 kg, fly apart perpendicular to each other with a velocity of 2 ms{eq}^{-1} {/eq} and 3 ms{eq}^{-1} {/eq}. Find the magnitude and direction of the third fragment.
2.5m/s at 36.87 degrees above the horizontal
Float
Physics
Senior High School
82,337
754203
Sam, whose mass is 73 kg, straps on his skis and starts down a 48 m high, {eq}20^{\circ} {/eq} frictionless slope. A strong headwind exerts a horizontal force of 200 N on him as he skies. Use work and energy to find Sam's speed at the bottom.
15 m/s
Float
Physics
Senior High School
177,446
630509
The value of the electric field at a distance of 27.9 m from a point charge is 75.9 N/C and is directed radially toward the charge. What is the charge? ( The Coulomb constant is {eq}8.98755 \times 10^{9} N.m^{2}/C^{2} {/eq})
6.57e-6 C
Float
Physics
Senior High School
184,134
366560
Calculate the final speed of a 110-kg rugby player who is initially running at 8.00 m/s but collides head-on with a padded goalpost and experiences a backward force of {eq}1.76 \times 10^4 {/eq} N for {eq}5.50 \times 10^{-2} {/eq} s.
-0.8 m/s
Float
Physics
Senior High School
130,222
423440
Two ice skaters stand at rest in the center of an ice rink. When they push off against one another the 61-kg skater acquires a speed of 0.63 m/s . If the speed of the other skater is 0.86 m/s , what is this skater's mass?
44.68 kg
Float
Physics
Senior High School
114,345
1313864
A 75kg pilot flies a plane in a vertical loop. At the top of the loop, when the plane is completely upside-down for an instant, the pilot hangs freely in the seat and does not push against the seatbelt or seat. The airspeed indicator reads 120m/s. What is the radius of the plane's loop?
1467.89 m
Float
Physics
Senior High School
54,380
1857463
A particle of mass {eq}3.818 \times 10^{-26} {/eq} kg and charge of magnitude {eq}3.2 \times 10^{-19} {/eq} C is accelerated from rest in the plane of the page through a potential difference of 145 V between two parallel plates. The particle is injected through a hole in the right-hand plate into a region of space co...
5.01e4 m/s
Float
Physics
Senior High School
190,903
857211
The yellow line emitted by a helium discharge tube in the laboratory has a wavelength of 587 nm. The same yellow line in the helium spectrum of a star has a measured wavelength of 590 nm. Calculate the speed of the moving star.
1.5e6 m/s
Float
Physics
Senior High School
45,262
1207974
Two point charges, {eq}\displaystyle +3.09\ \mu C {/eq} and {eq}\displaystyle -5.90\ \mu C, {/eq} are separated by {eq}\displaystyle 1.13\ m. {/eq} What is the electric potential midway between them?
7.04e+04 N/C
Float
Physics
Senior High School
187,942
1609572
{eq}Q_1 {/eq} (-55.0 mC) and {eq}Q_2 {/eq} (+96.0 mC) are located on the x-axis and are separated by a distance of 25.0 cm. {eq}Q_1 {/eq} is at the origin (0.00, 0.00, 0.00) and {eq}Q_2 {/eq} is to the right of {eq}Q_1 {/eq}. A third charge {eq}Q_3 {/eq} is located so that the net force on it due to the other two...
(-77.8, 0, 0)
Expression
Physics
Senior High School
18,051
1163775
Three identical very dense masses of {eq}7900\ kg {/eq} each are placed on the x axis. One mass is at {eq}x_1 = -130\ cm {/eq}, one is at the origin, and one is at {eq}x_2 = 440\ cm {/eq} What is the magnitude of the net gravitational force {eq}F_{grav} {/eq} on the mass at the origin due to the other two masses? T...
2.248e-3 N
Float
Physics
Senior High School
90,641
1577447
An object moving on a line, initially at rest, has an acceleration given by {eq}a(t) = 3t^2 + t {/eq}. At time t = 2 the object's position is {eq}s(2) = 3 {/eq}. Find s(t), the object's position at any time t.
s(t) = t^4/4 + t^2/2 - 3
Expression
Physics
University
196,862
514947
Suppose a soccer player kicks the ball from a distance 19 m toward the goal. Find the initial speed of the ball if it just passes over the goal, 2.4 m above the ground, given the initial direction to be 38{eq}^{\circ} {/eq} above the horizontal.
15.1 m/s
Float
Physics
Senior High School
111,705
285158
Steam at 180{eq}^o {/eq}C (saturated) enters a 10 cm diameter, 0.4 mm thick, 150 m long carbon steel pipe which is exposed to the elements. Air flows across the pipe at 10 m/sec. Air temperature is 20 {eq}^o {/eq}C. Convective heat transfer of stem to the pipe is very high. Emissivity of the pipe is estimated at 0.8....
40.33 kW
Float
Physics
University
76,513
1930411
The force {eq}F = 4i - 4j {/eq} moves an object {eq}\rm 5 \ ft {/eq} along the x-axis in the positive direction. Find the work done if the unit of force is the pound.
20 ft-lb
Integer
Physics
Senior High School
25,787
13890
A 86.3 kg horizontal circular platform rotates freely with no friction about its center at an initial angular velocity of 1.77 rad/s. A monkey drops a 9.15 kg bunch of bananas vertically onto the platform. They hit the platform at 4/5 of its radius from the center, adhere to it there, and continue to rotate with it. Th...
1.06 rad/s
Float
Physics
University
38,222
771351
A small conductive rod of length 1.3 m moves with a constant velocity v=15 m/s in a direction parallel to a long wire carrying a current of 34 A. The the axis of the rod is perpendicular to the direction of the wire and the distance between the wire and the closest end of the rod is 0.35 m. Calculate the electric poten...
1.582e-4 V
Float
Physics
University
217,988
1321626
What is the initial angle of projection of a projectile for which the range and the maximum height are equal?
76 degrees
Integer
Physics
Senior High School
8,757
354577
A worker released boxes at the top of a ramp. From the bottom of the ramp, the boxes slide 10 m across the floor to a barrier wall. If the ramp is at an elevation angle of {eq}20^{\circ} {/eq}, how long must the ramp be if the boxes are the reach the wall 2.0 s after leaving the ramp?
3.73 m
Float
Physics
Senior High School
78,421
1459935
How much heat must be added to 4.00 kg of aluminum to cause its temperature to rise from {eq}0^{\circ}\rm C {/eq} to {eq}22^{\circ}\rm C {/eq}? Answer in Joules.
7.9e4 J
Float
Physics
Senior High School
177,456
583612
A steel cylinder contains 98.0 moles of oxygen gas at a temperature of 38 degrees C and a pressure of 740 torr. After some of the oxygen gas has been used, the pressure is reduced to 332 toor at a temperature of 24 degrees C. What mass of oxygen gas is removed from the cylinder?
1817.4 g
Float
Physics
Senior High School
59,508
523217
The frequency of a radar is {eq}780 \ MHz {/eq}. The frequency of the reflected wave from aeroplane is increased by {eq}2.6 \ kHz. {/eq} The velocity of the aeroplane is: a) {eq}2 \ km/s {/eq} b) {eq}1 \ km/s {/eq} c) {eq}0.5 \ km/s {/eq} d) {eq}0.25 \ m/s {/eq}
c
Multiple Choice
Physics
Senior High School
174,472
1006007
What uniform magnetic field, applied perpendicular to a beam of electrons moving at {eq}\displaystyle 1.4 \times 10^6 m/s {/eq} is required to make the electrons travel in a circular orbit of radius {eq}\displaystyle 0.40 m? {/eq}
1.9e-5 T
Float
Physics
Senior High School
69,187
1093570
An object moves in an electric field from a position of {eq}\displaystyle \text{ 11cm to 47cm.} {/eq} The field has a strength of {eq}\displaystyle 2x^4 + 8x^3 V/m. {/eq} What is the change in voltage?
0.1065V
Float
Physics
University
42,784
267627
A solenoid is made of N = 3500 turns, has length L = 15 cm, and radius R = 1.1 cm. What is the magnetic field at the center of the solenoid?
B = μ_0 (N/L)I
Expression
Physics
Senior High School
3,688
103764
A helicopter is ascending vertically with a speed of 6.50 m/s. At a height of 55 m above the Earth, a package is dropped from a window. How much time does it take for the package to reach the ground? (Hint: The package's initial speed equals the helicopter's.)
4.08 secs
Float
Physics
Senior High School
23,780
2101782
What is the acceleration of a vehicle that changes its velocity from 120 km/h to a dead stop in 7 s? Answer in km/h.
-4.762 m/s^2
Float
Physics
Senior High School
90,669
153943
A boat heads directly across a river {eq}270 \ m {/eq} wide. It takes it {eq}520 {/eq} seconds to cross, but it ends up {eq}170 \ m {/eq} downstream. (a) What is its speed relative to the water? That is, how fast is the boat?
0.51 m/s
Float
Physics
Senior High School
146,568
1173997
A model train, with a mass of #12 kg#, is moving on a circular track with a radius of #6 m#. If the train's kinetic energy changes from #120 j# to #36 j#, by how much will the centripetal force applied by the tracks change by?
-28 N
Integer
Physics
Senior High School
42,183
1474029
An object has a mass of #4 kg#. The object's kinetic energy uniformly changes from #128 KJ# to # 48 KJ# over #t in [0, 12 s]#. What is the average speed of the object?
207.9ms^-1
Float
Physics
Senior High School
186,215
1909231
The electric field between two charged parallel plates is {eq}3500 \ N / C {/eq}. A {eq}0.000012 \ kg {/eq} pith ball carries a charge of {eq}6 \times 10^{-11} \ C {/eq}. The Ball is held at the midpoint of the plates. If released, how much kinetic energy does the ball gain traveling {eq}2 \ cm {/eq} towards th...
4.4e-9 J
Float
Physics
Senior High School
218,723
1862151
Three deer, A, B, and C, are grazing in a field. Deer B is located 61 m from dear A at an angle of 53 degrees north of west. Deer C is located 75 degrees north of east relative to dear A. The distance between deer B and C is 93 m. What is the distance between deer A and C? (Hint: Consider the law of cosines.)
117 m
Integer
Physics
Senior High School
96,856
385288
A 7 liter balloon at 22°C is carried outside where the temperature is -3°C. What is its new volume?
6L
Integer
Physics
Senior High School
90,040
574672
It takes 26 J of energy to move a(n) 0.23 mC charge from one plate of a 20 {eq}\mu {/eq}F capacitor to the other. How much charge is on each plate?
2.26 C
Float
Physics
University
124,801
982083
A very long insulating cylinder of charge of radius 2.10 cm carries a uniform linear density of 13.0 nC/m . If you put one probe of a voltmeter at the surface, how far from the surface must the other probe be placed so that the voltmeter reads 200 V ? Show work
11.15 cm
Float
Physics
University
129,246
552567
A particle moves on a line so that its position at time t seconds is {eq}p(t) = 3t^3 {/eq} meters to the right of the origin. Find the time c in the interval (4,8) for which the velocity of the particle at time c is equal to the average velocity on the interval {eq}[4,8]. {/eq}
6.11 sec
Float
Physics
Senior High School
111,686
1623471
A piece of wool is used to charge two plastic spheres. When the spheres are held 300mm apart, they repel each other with 8.00N of force. If the wool ends up with a surplus positive charge of 23.5 {eq}\mu {/eq}C, what is the charge on each of the two spheres? Enter your answers using two significant digits separated by...
-1.94 x 10-5 C and -4.14 x 10-6 C
List
Physics
Senior High School
64,225
917341
A train is traveling south at 23.5 m/s when the brakes are applied. It slows down with a constant rate to a speed of 5.01 m/s in a time of 8.73 s. How far does the train travel during the 8.73 s?
124.33 m
Float
Physics
Senior High School
210,875
1757810
A hot lump of 36.336 g of copper at an initial temperature of 82.0 C is placed in 50.0 mL {eq}H_2O{/eq} initially at 25.0 C and allowed to reach thermal equilibrium. Assuming no heat is lost to the surroundings, find the final temperature of the copper and water.
28.49^°C
Float
Physics
Senior High School
168,962
1700164
Are the properties of noncrystalline materials anisotropic?
No
Boolean
Physics
Senior High School
106,404
22397
In a refrigeration system, ammonia enters the expansion valve at 24°C and 10 bar and exits at 1 bar. The refrigerant undergoes a throttling process. Find the quality of the refrigerant exiting the expansion valve.
0.197 or 19.7%
Percentage
Physics
University
184,488
1282246
Imagine a car driving up a hill toward a stop sign. The driver allows the car to naturally slow down until it momentarily comes to a stop and rolls back some distance. Suppose your group gets a result of 4.95 ± 0.07 m/s² for your position vs. time-squared graph. What is the minimum value of the acceleration due to grav...
4.95 ± 0.07 m/s²
Expression
Physics
Senior High School
27,939
418880
A 10 foot ladder is leaning against a wall. If the top of the ladder slides down the wall at a rate of 2 feet per second, how fast is the bottom of the ladder moving along the ground when the bottom of the ladder is 5 feet from the wall?
3.4641 ft/s
Float
Physics
Senior High School
145,630
91133
A certain car has a fuel efficiency of 16.0 miles per gallon (mi/gal). Express this efficiency in kilometers per liter (km/L).
6.77 km/L
Float
Physics
Senior High School
204,673
540991
An 11 kg crate is pulled by a force of 150 N (parallel to the incline) up a rough {eq}35^o {/eq} incline. The crate has an initial speed of 1.65 m/s. The crate is pulled a distance of 8.21 m on the incline by a 150 N force. u=0.324 The acceleration of gravity is {eq}9.8\ m/s^2 {/eq}. Answer in units of J.
489 J
Float
Physics
Senior High School
106,576
993737
A {eq}3.0 \; \mu C {/eq} positive charge is located at the origin and a {eq}2.0 \; \mu C {/eq} positive charge is located at (0.0 m, 1.0 m). Find the point between them where the electric field strength is zero.
(0.0 m, 0.55 m)
Expression
Physics
Senior High School
214,545
1519023
Find a mathematical model for the verbal statement: "The gravitational attraction F between two objects of masses {eq}m_1 {/eq} and {eq}m_2 {/eq} is proportional to the product of the masses and inversely proportional to the square of the distance r between the objects."
{eq}F = \frac{k m_1m_2}{r^2}{/eq}
Expression
Physics
Senior High School
220,828
1294546
Two particles M1 and M2 of mass 0.3 kg and 0.45 kg respectively are placed 0.25 m apart. A third particle M3 of mass 0.05 kg is placed between them. Calculate the gravitational force acting on the M3 if it is placed 0.1 m from the M2.
1.055e-10 N
Float
Physics
Senior High School
114,177
706511
A group of engineers is preparing a satellite to land by moving it 10% closer to Earth in each rotation. Which statement is correct about the rotational inertia of the satellite? O Rotational inertia first decreases and then increases as the satellite is ready to land. O Rotational inertia decreases proportional t...
A
Multiple Choice
Physics
Senior High School
92,635
1418967
Steel surfaces can be hardened by carburization. During one such treatment at {eq}1000^{\circ}C {/eq}, there is a drop in carbon concentration from 5 to 4% at carbon between 1 and 2 mm from the surface of the steel. Estimate the flux of carbon atoms into the steel (in atoms {eq}m^{-2}s^{-1} {/eq}) in this near-surfac...
2.452e19 atom/m^2s
Float
Physics
University
6,939
1913579
How much energy is consumed in 2.0 h by an electrical resistance of 385 {eq}\Omega {/eq} when the potential applied across it is 99.0 V?
0.051 kWh
Float
Physics
Senior High School
175,016