Practice Exams Flashcards
Which of the situations described below involves an object whose acceleration is zero?
Circle all that apply.
A. A car skidding to a stop on a straight, level road
B. A book sitting on a table
C. A bullet that has been fired straight up into the air and is at the highest point of its motion
D. A child riding a merry-go-round while no one is pushing
E. A bicyclist coasting down a hill (ignore air resistance)
F. A train traveling at a constant speed on a straight, level track
G. A train traveling at a constant speed while rounding a turn
B. A book sitting on a table
F. A train traveling at a constant speed on a straight, level track
The normal force is always
A. equal to weight.
B. perpendicular to a surface.
C. vertically upward.
D. acting on an object in free fall.
B. perpendicular to a surface.
Of the objects described below, which one has a nonzero net force acting on it?
A. A parked car
B. A horse rounding the curve on a racetrack while maintaining a constant speed
C. A box sliding down a ramp at constant speed
D. None of the above
B. A horse rounding the curve on a racetrack while maintaining a constant speed
When a basketball player dunks the basketball, the magnitude of the force exerted on his hand by
the ball is __________________ the magnitude of the force exerted on the ball by his hand.
A. less than
B. the same as
C. greater than
D. The ball doesn’t exert a force on his hand.
B. the same as
For each of the situations described on the left, one of the forces (or its component) on the right
provides the centripetal force. Write the letter of the force in the blank next to the appropriate
situation.
_____ Mars orbits the Sun
_____ A car rounds a curve on a level road
_____ A car travels around a banked curve when the road is icy (i.e. frictionless)
_____ A pendulum passes through the lowest point
A. Tension
B. Gravity
C. Normal force
D. Friction
B
D
C
A
A hawk flying horizontally catches a sparrow in mid-air. This causes the hawk’s momentum to
change by Δ𝑝⃗ℎ𝑎𝑤𝑘. The hawk’s mass is 10 times the sparrow’s mass. The change in the sparrow’s
momentum, Δ𝑝⃗𝑠𝑝𝑎𝑟𝑟𝑜𝑤, is
A. 10Δ𝑝⃗ℎ𝑎𝑤𝑘
B. −10Δ𝑝⃗ℎ𝑎𝑤𝑘
C. Δ𝑝⃗ℎ𝑎𝑤𝑘
D. −Δ𝑝⃗ℎ𝑎𝑤𝑘
E. 0
D. −Δ𝑝⃗ℎ𝑎𝑤𝑘
A hoop and a solid sphere have the same mass and radius. Each experiences a net torque of 10 N∙m
about an axis through its center. Which one has the greater angular acceleration?
A. the hoop
B. the sphere
C. their accelerations are the same
D. not enough information
B. the sphere
A child riding by herself on a spinning merry-go-round wishes to increase the rate of rotation
(angular speed) of the merry-go-round without touching the ground. What should she do?
A. move toward the center
B. move toward the edge
C. jump up and down
D. sit down
A. move toward the center
Oil is less dense than vinegar. If you open a bottle of oil and a bottle of vinegar, each of which is
filled to a height of 20 cm, which bottle has the greater pressure at the bottom?
A. the vinegar
B. the oil
C. the pressures are the same
D. it depends on how wide the bottles are
A. the vinegar
A golf ball and a ping-pong ball are exactly the same size. When placed in a bucket of water, both
of them float, but the golf ball floats “low” in the water (i.e. most of it is below the surface), and the
ping-pong ball floats “high” in the water (i.e. most of it is above the surface). Which ball
experiences the greater buoyant force?
A. the golf ball
B. the ping-pong ball
C. the buoyant forces are the same
D. more information is needed
A. the golf ball
Now a metal ball the same size as the golf ball is dropped into the bucket of water. The metal ball
sinks to the bottom. The buoyant force on the metal ball is ___________ the buoyant force on the
golf ball.
A. equal to
B. less than
C. greater than
D. more information needed
C. greater than
for motion along a straight line is it possible for speed to be constant while acceleration is not zero?
This is not possible
When an object moves along a curved path, is it possible for acceleration to be zero?
No
