Chapter 2

Your backpack falls from your seat onto the floor of a bus that is moving at a constant speed of 20 km/h. During the fall, its horizontal speed, relative to the road is

20 km/h

If a 150 lbs person stands on a pair of bathroom scales, and leans so one of the scales reads 100 lbs, the the other scale

reads 50 lbs

An object that maintains its state of motion because

it has mass

A force is a vector quantity because it has both

magnitude and direction

The law of inertia applies to

objects at rest & moving objects

Ten seconds after starting from rest, a freely falling object will have a speed of about

100 m/s

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

0N

A 20N force and a 15N force act on an object in opposite directions. What is the net force on the object?

5 N

A 10N falling object encounters 4N of air resistance. The magnitude of the net force on the object is

6N

Consider an object in freefall. Each second the object falls, what happens to the distance?

It falls with a greater distance than in the second before.

Galileo found that a ball rolling down one inclined plane rolls how far up another incline plane?

To nearly the same height as it initially started.

A bicycle traveling at a steady speed in a circle may have

a constant speed

Whirl a rock at the end of a string and it follows a circular path. If the string broke, what path would it take?

a straight line path

The two measurements necessary for calculating average speed are

distance and time

If you push a crate across the floor with the force of 100N and it slides at a constant velocity, then the force of friction between the crate and the floor is

equal to 100N

When you stand at rest on a pair of bathroom scales, the readings on the scales will always add to...

equal your weight

A truck is moving at a constant velocity, inside the storage compartment, a rock is dropped from the midpoint of the ceiling and strikes the floor below. The rock hits the floor..

exactly below the midpoint of the ceiling

A sheet of paper can be withdrawn from under a container of milk without toppling if the paper is jerked quickly. This best demonstrated that the milk carton has

inertia

The force required to maintain an object at a constant velocity in free space is equal to

zero