HW Assignment 2 and 3

A hockey puck slides across a frozen pond. If ice friction and air resistance are neglected, the force needed to keep the puck sliding at constant velocity is

0 N

A 1-kg ball is thrown straight up at 10 m/s. Neglecting air resistance the net force that acts on the ball when it is halfway to the op of its path is

10N

What is the mass of a ball moving at 4 m/s with a momentum of 48 kg∙m/s?

12 kg

A 10kg block is pushed across a friction-free horizontal surface with a horizontal force of 20N. The acceleration of the block is

2 m/s2

A 1000-kg car acceleration at 2 m/s2. What is the net force exerted on the car?

2000N

What is the speed of a 4-kg ball with a momentum of 12 kg∙m/s?

3 m/s

A block is dragged at constant velocity across a level surface by a force of 6 N. What is the force of friction between the block and the surface?

6N

A boxer punches a sheet of paper in midair from rest to a speed of 40 m/s in 0.05 s. If the mass of the paper is 0.01 kg, the force of the punch on the paper is

8.0 N

If the mass of an object does not change, a constant net force on the object produces constant

Acceleration

A mack truck and a mini cooper traveling at the same speed collide head-on. The collision force is the greater on the

Same on both

If you jump vertically while inside a fast-moving train that is slowing down, you land

a bit ahead of your original position

When you jump from an elevated position you usually bend your knees upon reaching the ground. By doing this, the contact time is about 10 times more than for a stiff-legged landing and the average force your body experiences is reduced by

about 10 times

Newton's second law focuses on

acceleration

While a car travels around a circular track at constant speed, its

acceleration is zero. velocity is zero. both of these none of the above None of the above

A heavy object and a light object in a vacuum are dropped at the same time from rest. The heavy object reaches the ground

at the same time as the light object

You're in a fast-moving train traveling at constant velocity. If you jump straight up you land

at your original position

A given net force propels an object along a straight-line path. If the mass were doubled, its acceleration would

be half

Action and reactio pairs of forces always act on

different bodies

A given net force propels an object along a straight-line path. If the net force were doubled, its acceleration would

double

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

A space probe in remote outer space continues moving

even though no force acts on it

If your automobile runs out of fuel while driving, the engine stops. You don't come to an abrupt stop because of

inertia

When a cannon fires a cannonball at a given speed, the smaller recoil speed of the cannon is due to differences in

masses

An iron ball and wooden ball of the same size are dropped simultaneously from a tower and reach the ground at the same time. The iron ball has a greater

momentum

An object in motion is an object that has

momentum

Inertia is defined as a

property of matter

The force exerted on the tires of the car to directly accelerate the car along a road is exerted by the

road

A karate expert executes a swift blow and breaks a cement block with her bare hand. The magnitude of the force on her hand is

the same as the force applied to the block.

The distinction between impulse and force involves the

time the force acts

An object in motion tends to remain in motion

without the need of a force