A 10-kg mass and a 2.0-kg mass are connected by a light string
over a massless, frictionless pulley. If g = 9.8 m/s2, what is the
acceleration of the system when released? Correct Answers
a=g(m2-m1)/(m2+m1)
=6.53
A 70.0 kg student stands on a bathroom scale in an elevator.
What is the reading on the scale (a)When the elevator is moving
upward at a constant 0.50 m/s?(b)When the elevator is
accelerating downward at 1.00 m/s2 Correct Answers
N=m(a+g)
N=m(-a+g)
A ball sits at rest on a horizontal table top.The gravitational
force on the ball (its weight) is one half of an action-reaction
pair. Which force is the other half?
A. the force of the Earth's gravity on the ball
B. the upward force that the table top exerts on the ball
C. the upward force that the ball exerts on the Earth
D. the downward force that the ball exerts on the table top
E. the frictional force between the ball and the table top Correct
Answers C. the upward force that the ball exerts on the Earth
A ball sits at rest on a horizontal table top.The weight of the ball
is equal to the magnitude of the upward force that the table top
exerts on the ball. Why?
, A. This is a consequence of Newton's first law.
B. This is a consequence of Newton's third law.
C. Because we assume that the table top is perfectly rigid.
D. Two of the above three statements are correct.
E. All of the first three statements are correct. Correct Answers
A. This is a consequence of Newton's first law.
A crate is sitting in the center of a flatbed truck. As the truck
accelerates to the east, the crate moves with it, not sliding on the
bed of the truck. In what direction is the friction force exerted by
the bed of the truck on the crate?
1.to the west
2.to the east
3.There is no friction force, because the crate is not sliding.
Correct Answers 2.to the east
A horse is hitched to a wagon. Which statement is correct?
A. The force that the horse exerts on the wagon is greater than
the force that the wagon exerts on the horse.
B. The force that the horse exerts on the wagon is less than the
force that the wagon exerts on the horse.
C. The force that the horse exerts on the wagon is just as strong
as the force that the wagon exerts on the horse.
D. The answer depends on the velocity of horse and wagon.
E. The answer depends on the acceleration of horse and wagon.
Correct Answers C. The force that the horse exerts on the
wagon is just as strong as the force that the wagon exerts on the
horse.