1. Forces
A Review

2. The force that always acts opposite to the direction of motion
Friction

3. It would be easiest ride your bike across
A: gravel
B: sand
C: the grass
D: a side walk

4. Buoyancy is the upward force created by liquids
Archimedes principle: the buoyant force is equal to weight of the water displaced.

5. The cube has force of gravity 10 Newtons acting on it
The cube has force of gravity 10 Newtons acting on it. What is the Buoyant force?
A: 10 Newtons
B: more than 10 Newtons
C: less than 10 Newtons
D: not enough information

6. Gravity Pulls objects with mass together More mass=more gravity
Closer together=more gravity

7. Hector weighs 60 kg on Earth what is his weight if he went to the moon?

8. The gravitational force between each planet and the Sun is
A: the same because it is only affected by the gravity of the Sun
B: larger for planets farther from the Sun because more force is needed to keep them in orbit
C: determined by the mass of the Sun, the mass of the planet, and the planet’s distance from the Sun.

9. Newton’s First Law of Motion
Part 1: An object at rest remains at rest unless acted on by an unbalanced force

10. Newton’s First Law of Motion
Part 2: An object in motion remains in motion at constant speed and in a straight line unless acted on by an unbalanced force

11. The more mass an object has the more inertia it has.
True or
False

12. Newton’s Second Law of Motion
The acceleration of an object depends on the mass of the object and the amount of force applied
Part 1: Acceleration depends on mass
Part 2: Acceleration depends on force

13. What happens when the force increases?
The stronger the force on an object, the greater its acceleration.

14. What happens if the mass is increased?
There must be more force to keep the same acceleration
5 N
8 N

15. Newton’s Third Law of Motion
Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first.

16. Forces act in pairs Action force=the force that does the first action
Reaction force=the force that occurs as a response to the action force
Action: the exhaust pushes
down
Reaction: the rocket moves up

17. According to Newton’s 3rd law, forces always act in _______ pairs
A: equal but opposite
B: unequal but opposite
C: equal but complementary

18. 1. Stepping on a wagon and watching it move away from you
Name that law
1. Stepping on a wagon and watching it move away from you
3rd

19. 2. If a driver turns a corner too quickly your body leans sideways
Name that law
2. If a driver turns a corner too quickly your body leans sideways
1st

20. 3. Explains the relationship between force, mass and acceleration
Name that law
3. Explains the relationship between force, mass and acceleration
2nd

21. Name that law
4. When you walk, you push on the sidewalk, and the side walk pushes on you with equal force
3rd

22. 5. A bowling ball knocks down a set of pins and keeps rolling
Name that Law
5. A bowling ball knocks down a set of pins and keeps rolling
1st

23. Name that Law
6. A soldier shoots a rifle and the gun moves back towards his shoulder
3rd

24. Name that Law
7. A boy wants to travel faster on his bike so he peddles with more force
2nd

25. How many of these are forces?
Inertia Mass
Friction Buoyancy
Newtons Weight
Compression Tension
Equilibrium Distance
Gravity Normal