Milestone Practice - Force

What two quantities must stay the same in order for an object to have a constant velocity?

• The speed and kinetic energy must be constant.

• The speed and mass of the object must be constant.

• The speed and direction of travel must be constant.

• The force applied to and direction of travel must be constant.

Consider the car driving around a circular track. Once started, the driver maintains a speed of 45 m/h. Compare the driver's velocity with his acceleration in this case.

• The car is accelerating because it is changing direction but the velocity is constant.

• The car is traveling at a constant rate of speed so it is not accelerating and the velocity does not change.

• Acceleration is the change in velocity so the car is experiencing a change in velocity and it is accelerating.

• The car is traveling at a constant rate of speed so it is not accelerating but the velocity changes because the direction the car travels is constantly changing.

The measure of the distance an object travels in a certain length of time is the object's

• Direction

• Energy

• Position

• Speed

Bobby is riding his bike down the road at a speed of 10 miles per hour. Ahead of him, he sees another rider, moving in the same direction. Bobby is catching up with the rider ahead of him.

• The same speed as Bobby's.

• Slower than 10 mph.

• Much faster than 10 mph.

• About 5 mph.

A car's position in relation to time is plotted on the graph. What can be said about the car during segment B?

• The car travels for 80 seconds during segment B.

• The car is traveling faster during segment B than in segment C.

• The car has come to a stop and has zero velocity.

• The car is traveling with a constant velocity due to the flat line of the graph.

Jose and Gina are studying balanced and unbalanced forces and are challenged to test their theories. Predict the result when Jose applies 6 Newtons of force to one side of a box and Gina applies 6 Newtons of force to the other side of the box.

• The box does not move.

• The box moves toward Gina.

• The box moves toward Jose.

• The box moves upwards

When the net force of opposite forces is zero, the forces are

• not even

• unequal

• unbalanced

• balanced

The law of inertia states that an object in motion will stay in motion, and an object at rest will stay at rest unless acted upon by an unbalanced force. Which law of motion is this describing?

• Newton's First Law

• Newton's Second Law

• The law of gravity

• Newton's Third Law

A train rolls to a stop along a horizontal track without the conductor applying the brakes. What answer choice BEST explains why this occurred?

• The train ran out of momentum.

• The opposing force of friction stopped the train

• The natural state of the train is not to be in motion

• The force of gravity slowed the train until it stopped.

How does this photograph illustrate Newton's third law of motion?

• The greater the swimmer's acceleration, the more force applied and the lower his mass.

• The more force the swimmer applies back on the wall, the faster his movement forward in the water.

• In order for the swimmer to move forward in the water there must be an unbalanced force acting on the him.

• The force acting forward is greater than the force acting in the opposite direction: the swimmer accelerates.