Download Friction

Name:_____________________________________
Date:_____________
Friction and Gravity
1. True or False-When two surfaces rub, the irregularities of one surface get caught
on those of the other surface.
2. What is friction?
3. Friction acts in a direction ___________________ to the object’s direction of
motion.
4. The strength of the force of friction depends on what two factors?
5. How is friction involved in sledding and skiing?
6. Why does some friction occur with seemingly smooth surfaces?
7. Which kind of friction requires more force to overcome, rolling friction or sliding
friction?
8. What kind of friction occurs when moving parts have ball bearings?
9. How does oil between machine parts reduce friction?
10. A force that pulls objects toward each other is called_____________.
11. True or False-The force that makes an apple fall to the ground is the same force
that keeps the Earth orbiting the sun.
12. What does the universal law of gravitation state?
13. The force of attraction between two objects varies with what two factors?
14. What is weight?
15. How is weight different from mass?
16. Weight is usually measured in ____________________.
17. True or False-On the moon, your mass would be less than it is Earth, but your
weight would be the same.
18. When is an object said to be in free fall?
19. Near the surface of the Earth, what is the acceleration of an object due to the force
of gravity?
20. Objects falling through air experience a type of fluid friction called
_________________
21. The greatest velocity a falling object reaches is called_____________.
22. True or False- The greater the surface area of an object, the greater the air
resistance.
23. An object that is thrown is called a _________________.
24. True or False-An object that is dropped will hit the ground before an object that is
thrown horizontally from the same height.
Answer the following using complete sentences.
1. What are two factors that affect the friction force between two surfaces?
2. What is one way you could reduce the friction between two surfaces?
3. The acceleration due to gravity of all objects in free fall is the same. Why, then,
do some objects fall through the air at a different rate than others?
4. How does mass differ from weight?
5. What two factors affect the gravitational force between two objects?
Newton’s First and Second Laws
1. For an unmoving object to start moving, a(n)__________________ has to act on
it
2. What is Newton’s first law of motion?
3. What is inertia?
4. What is another name for Newton’s first law?
5. The amount of inertia an object has depends on its_________________.
6. What is Newton’s second law of motion?
7. What is the equation that describes the relationship among the quantities of force,
mass, and acceleration?
8. What are the two units that are the same measurement for force?
9. How can you use Newton’s second law to find force?
10. What are two ways to increase the acceleration of an object?
11. What is inertia?
12. How much force is needed to accelerate a 3 kg skateboard at 5 m/s2?