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Homework exercises on Forces for a Physical Science course. Also refer to Physics, motion, inertia, momentum, friction,  education, distance learning, Newton,  School for Champions. Copyright © Restrictions

Forces - Homework Answers

After you have completed the Forces Homework, you can refer to these answers. Although it is better to have known the answer from your reading, the process of writing the correct answer on your homework sheet will help you remember the concepts.

1. What causes an object to move?

A force.

2. What is the relationship between force, mass, and acceleration?

Force = mass x acceleration (F = ma).

3. If you double the mass of an object, what must the force be for the same acceleration?

Twice as much.

4. What is an impulse force?

.A force applied for a very short time. Like an explosion or hitting a ball with a bat.

5. What units do you use to measure force?

Pounds in English system and Newtons in metric system.

6. What happens to a moving object when a force is applied at an angle to the motion?

It changes direction.

7. What happens when several forces are applied in a line?

Those in the same direction add, while those in opposite directions subtract.

8. What are vectors used for?

A graphical representation of the summation of forces in different directions.

9. What are the two classes of forces?

Direct contact forces and forces at a distance.

Inertia

1. What is one principle in the Law of Inertia?

Things moving keep moving; things that are not moving tend to stay that way..

2. If the Law of Inertia is true, why does a ball rolling on the floor slow down and stop?

The force of friction.

3. Why does the trick work where you pull a table cloth from under dishes on top without having the dishes fly off the table?

The inertia of the heavy dishes is greater than the friction of the table cloth..

4. Why is there a force when you swing an object around on a string?

Centripetal force. Things want to go in a straight line.

5. What would happen to the moon without the force of gravity?

It would fly off into space.

Momentum

1. What is momentum?

When an object is moving, it possesses a quality called momentum, which means the object tends to keep moving. Momentum = mass x velocity (P = mv).

2. How fast would the 180 pound Superman have to fly to have the same momentum as a 18,000 pound truck traveling at 30 miles per hour?

3000 mph.

3. What is the Law of the Conservation of Momentum?

In a closed system, the momentum is constant.

Where can you go from here?