PHY 102 HW4

An 80 kg man on ice skates pushes a 40 kg boy, also on skates, with a force of 100 N. The force exerted by the boy on the man is

100 N

A ball is moving at 3 m/s and has a momentum of 48 kg m/s. What is the ball's mass?

16 kg

A force accelerates an object of mass M. A second object requires twice the force to produce the same acceleration. What is the mass of the second body?

2M

A net force of 64 N acts on a mass of 16 kg. What is the acceleration of the object?

4 m/s/s

A force accelerates an object of mass M. The same force applied to a second object produces 4 times the acceleration. What is the mass of the second object?

M/4

A spaceship in deep outer space is moving with a constant speed in a straight line. Which of the following is true?

a net force of zero is acting on the spaceship

The net force on a moving object suddenly becomes zero. The object then

continues at a constant velocity

A freight train rolls along a track with considerable momentum. If it rolls at the same speed but has twice as much mass, its momentum is

doubled

Which of the following statements is Newton's 3rd law?

for every action there is an equal and opposite reaction

Which of the following statements is Newton's 2nd law?

force equals mass times acceleration.

If you apply the same force to objects with masses M and 4M, the acceleration of mass M is

four times the acceleration of mass 4M

Padded dashboards in cars are safer in an accident than nonpadded ones because an occupant hitting the dash has

increased time of impact

The SI unit of force is the

newton

A satellite is sent out in space. Which of the following is true of the satellite as it moves away from the earth?

the satellite's mass remains constant and its weight decreases

A hockey puck is set in motion across a frozen pond. If friction and air resistance are neglected, the force required to keep the puck sliding at constant velocity is

zero