Name: ______Period: _____ Date: ______Self Assessment: Newton’s Laws of Motion
1. Defined unbalanced forces. How can you tell by looking at an object if the forces on
it are unbalanced?
2. Explain what inertia is and what other property of matter it depends on.
3. Which object has more inertia, a golf ball or bowling ball? Explain.
4. Earth is pulling me down. We call that gravity. If gravity is the action, what is the
equal and opposite reaction?
Identify which Law of Motion each is by placing a 1, 2 or 3 in the blank
5. ______You’re in a car that slams on the brakes and you go flying forward
6. ______When you hit a nail with a hammer, they both feel the same force
7. ______The nail in #2 moves more than the hammer does.
8. ______I can throw a baseball farther than a shotput.
9. ______When I throw the baseball, it would go straight, if it weren’t for gravity and
air resistance.
10. ______It takes more effort to push a full shopping cart than an empty one.
11. ______The weight of an object is its mass times the acceleration due to gravity.
12. ______I hit a ball with a bat. The same force is exerted on both objects.
13. ______I spin a yoyo in a circle. If I let go of the string, it flies off in a straight line.
True or False. Explain.
14. When forces are balanced something does not move.
15. When forces are balanced something moves at a constant speed.
16. When forces are balanced something accelerates.
17. When forces are unbalanced something does not move.
18. When forces are unbalanced something moves at a constant speed.
19. When forces are unbalanced something accelerates.
20. Draw the forces acting on a ball as I drop it.
21. Draw the forces acting on a soccer ball while I’m kicking it.
22. Draw the forces acting on a soccer ball after I kick it and it’s flying into the goal.
Use the formula F=ma to solve the following. Show your work! Don’t forget the correct
units and sig figs.
23. ______What is the acceleration of a truck with a mass of 1200 kg
moving because of a 7800 N force?
24. ______What is the mass of a soccer ball that is accelerating at
11.5 m/s/s because of an applied force of 167 N?
Name: __Answer key__ Period: _____ Date: ______
Self Assessment: Newton’s Laws of Motion
1. Defined unbalanced forces. How can you tell by looking at an object if the forces on
it are unbalanced?
Total forces are not equal
The object accelerates (changes speed,
direction or both)
2. Explain what inertia is and what other property of matter it depends on.
Tendency of an object to resist changes in
motion
Depends on mass. More mass = more inertia
3. Which object has more inertia, a golf ball or bowling ball? Explain.
Bowling ball. It has more mass.
4. Earth is pulling me down. We call that gravity. If gravity is the action, what is the
equal and opposite reaction?
You are pulling back on the Earth! (Why doesn’t the Earth move then? Well, technically it does, but not a whole lot because it has more inertia)
Identify which Law of Motion each is by placing a 1, 2 or 3 in the blank
5. ___1___ You’re in a car that slams on the brakes and you go flying forward
6. ___3___ When you hit a nail with a hammer, they both feel the same force
7. ___2___ The nail in #2 moves more than the hammer does.
8. ___2___ I can throw a baseball farther than a shotput.
9. ___1__ When I throw the baseball, it would go straight, if it weren’t for gravity and
air resistance.
10. ___2___ It takes more effort to push a full shopping cart than an empty one.
11. ___2___ The weight of an object is its mass times the acceleration due to gravity.
12. ___3___ I hit a ball with a bat. The same force is exerted on both objects.
13. __1__ I spin a yoyo in a circle. If I let go of the string, it flies off in a straight line.
True or False. Explain.
14. When forces are balanced something does not move.
True…it can be not moving. But it is also true that it can move with a constant speed.
15. When forces are balanced something moves at a constant speed.
True. If the forces are balanced there is no change in motion, so it keeps doing whatever it was doing.
16. When forces are balanced something accelerates.
False. It takes unbalanced forces to change motion (accelerate) see Newton’s First Law of Motion.
17. When forces are unbalanced something does not move.
False. According to Newton’s First Law of Motion, unbalanced forces lead to acceleration…motion.
18. When forces are unbalanced something moves at a constant speed.
False. According to Newton’s First Law of Motion, unbalanced forces lead to acceleration (change in speed or direction or both).
19. When forces are unbalanced something accelerates.
True. Newton’s First Law of Motion says so.
20. Draw the forces acting on a ball as I drop it.
Friction/air resistance
Gravity
21. Draw the forces acting on a soccer ball while I’m kicking it.
Normal force
Friction/air resistance Kick (applied force)
Gravity
22. Draw the forces acting on a soccer ball after I kick it and it’s flying into the goal.
Friction/air resistance
Gravity
Use the formula F=ma to solve the following. Show your work! Don’t forget the correct
units and sig figs.
23. _6.5 m/s2_ What is the acceleration of a truck with a mass of 1200 kg
moving because of a 7800 N force?
F = ma 7800 = 1200 (a) (div. both sides by 1200)
a = 7800/1200
a = 6.5 (2 sig figs)
24. _14.5 kg _ What is the mass of a soccer ball that is accelerating at
11.5 m/s/s because of an applied force of 167 N?
F = ma 167 = (m) 11.5 (div. both sides by 11.5)
m = 167/11.5
m = 14.521739813 (3 sig figs)