A ball is thrown off of a 25-m-high cliff. Its initial velocity is 25 m/s, directed at an angle of 53° above the horizontal. How much time elapses before the ball hits the ground? (sin 53° = 0.80; cos 53° = 0.60; tan 53° = 1.3)
The velocity–time graph above represents a car on a freeway. North is defined as the positive direction. Which of the following describes the motion of the car?
The car is traveling north and slowing down
The car is traveling south and slowing down
The car is traveling north and speeding up
The car is traveling south and speeding up
The car is traveling northeast and speeding up
A free-body diagram includes vectors representing the individual forces acting on an object. Which of these quantities should NOT appear on a free-body diagram?
tension of a rope
Mass times acceleration
An object rolls along level ground to the right at constant speed. Must there be any forces pushing this object to the right?
Yes: the only forces that act must be to the right
Yes: but there could also be a friction force acting to the left
No: No forces can act to the right
No: While there can be forces acting, no force MUST act
The answer depends on the speed of the object
A satellite orbits the moon in a circle of radius R. If the satellite must double its speed but maintain a circular orbit, what must the new radius of its orbit be?
A strong hurricane may include 50 m/s winds. Consider a building in such a hurricane. If the air inside the building is kept at standard atmospheric pressure, how will the outside air pressure compare to the inside air pressure?
Outside pressure will be the same
Outside pressure will be about 2% greater
Outside pressure will be about 2% lower
Outside pressure will be about twice inside pressure
Outside pressure will be about half inside pressure
At room temperature, the rms speed of nitrogen molecules is about 500 m/s. By what factor must the absolute temperature T of the Earth change for the rms speed of nitrogen to reach escape velocity, 11 km/s?
T must decrease by a factor of 50
T must increase by a factor of 22
T must increase by a factor of 50
T must increase by a factor of 200
T must increase by a factor of 500
On which of the following physics principles does Kirchoff 's loop rule rest?
Conservation of charge
Conservation of Mass
Conservation of Energy
Conservation of Momentum
Conservation of angular momentum
The circular wire shown carries a current I in the counterclockwise direction. What will be the direction of the magnetic field at the center of the wire?
into the page
out of the page
A traveling wave passes a point. At this point, the time between successive crests is 0.2 s. Which of the following statements can be justified?
The frequency is 5 Hz
The wavelength is 5 m
The velocity of the wave is 5 m/s
The wavelength is 0.2 m
The wavelength is 68 m
The state of a gas in a cylinder is represented by the PV diagram shown. The gas can be taken through either the cycle ABCA, or the reverse cycle ACBA. Which of the following statements about the work done on or by the gas is correct?
In both cases, the same amount of net work is done by the gas
In both cases, the same amount of net work is done on the gas
In cycle ABCA net work is done on the gas; in cycle ACBA the same amount of net work is done by the gas
In cycle ABCA net work is done by the gas; in cycle ACBA the same amount of net work is done on the gas
In both cycles net work is done by the gs, but more net work is done by the gas in ACBA than in ABCA