Physics Chapter Two

A package falls off a truck that is moving at 30 m/s. Neglecting air resistance, the horizontal speed of the package just before it hits the ground is

About 30 m/s

Galileo's interpretation of motion differed from Aristotle's in that Galileo emphasized

time rates

The force of friction on a sliding object is 10 N. The applied force needed to maintain a constant velocity is

10N

A 300-kg bear grasping a vertical tree slides down at constant velocity. The friction force between the tree and the bear is

3000N

A man weighing 800 N stands at rest on two bathroom scales so that his weight is distributed evenly over both scales. The reading on each scale is

400 N

If your automobile runs out of fuel while you are driving, the engine stops but you do not come to an abrupt stop. The concept that most explains why is

inertia

When a rocket ship accelerating in outer space runs out of fuel, it

no longer accelerates

Galileo's use of inclined planes allowed him to effectively

slow down the acceleration of free fall

A sheet of paper can be withdrawn from under a container of milk without toppling it if the paper is jerked quickly.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

the milk carton has inertia

According to Newton's law of inertia, a railroad train in motion should continue going forever even if its engine is turned off. We never observe this because railroad trains

Always have forces that oppose their motion

An object in mechanical equilibrium is an object

At rest, moving with constant velocity, and having no acceleration.

A truck is moving at 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

The scientist to first introduce the concept of inertia was

Galileo

Hang from a pair of gym rings and the upward support forces of the rings will always

add up to your equal weight

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

add up to your equal weight

If no external forces are acting on a moving object, it will

continue moving at the same velocity

Whereas Aristotle relied on logic in explaining nature, Galileo relied on

experiment.

Whirl a rock at the end of a string and it follows a circular path. If the string breaks, the tendency of the rock is to

follow a straight-line path