1. Forces, Friction, and Gravity

2. Forces
Friction
Gravity
Misc.
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3. What is the difference in the effects of a
An unbalanced force causes a change in motion (slowing down, speeding up, starting, stopping, changing direction). A balanced force has no effect so the object does not move since the net force is 0.
What is the difference in the effects of a
balanced force vs. an unbalanced force?
Row 1, Col 1

4. What is the effect of friction on
Friction works in the opposite direction of motion so it causes an object to slow down or stop moving.
What is the effect of friction on
motion?
1,2

5. Gravity depends on ______ and _________ .
mass and distance
Gravity depends on ______
and _________ .
1,3

6. 90N to the left.
Two friends are trying to push a big rock. One friend was pushing the rock with a force of 25N to the left, but the rock would not budge. The other friend came to help with a push force of 65N to the left. What is the net force
that is being exerted on the rock?
1,4

7. What is the tool and unit
Tool: spring scale
Unit: Newton
What is the tool and unit
used to measure force?
2,1

8. Describe how mass and surface affect the amount of friction
mass- The greater the mass of the object, the more friction will exist.
surface- The rougher the surface, the more friction will exist. The smoother the surface, the less friction will exist.
Describe how mass and surface affect the amount of friction
that exists.
2,2

9. How is weight related to gravity?
Weight depends on the gravitational pull on an object. The more gravity that exists, the greater the amount of weight.
How is weight related to gravity?
2,3

10. A ball would move faster on a smooth surface
A ball would move faster on a smooth surface. An example of a smooth surface would be a tile floor.
Would a ball move faster on a smooth surface or a rough surface? Give an example of the type of surface the ball would move fastest on.
2,4

11. A hockey player hits a hockey puck into a goal. What are the forces
Forces: hockey stick, hockey players hands on hockey stick, ice, gravity, goal (which causes it to stop)
A hockey player hits a hockey
puck into a goal. What are the forces
being exerted on the puck?
3,1

12. Provide a positive example of friction and a
positive- walking, sand on ice, baseball gloves, sneakers
negative-clothes getting worn out, car parts heating up, water and wind erosion
Provide a positive example of friction and a
negative example of friction.
3,2

13. Why does an astronaut weigh more on
Earth has more gravity than the moon because it has more mass. Since weight depends on gravity, the weight will be greater on Earth.
Why does an astronaut weigh more on
Earth than on the moon?
3,3

14. Gravity is the force of attraction between two objects.
What is gravity?
3,4

15. What is the relationship between
The more mass an object has, the more force it requires to move the object.
What is the relationship between
mass and force?
4,1

16. What are two ways to decrease
1. add a liquid or lubricant 2. add wheels 3. make the surface smoother 4. decrease mass
What are two ways to decrease
friction?
4,2

17. How does gravity affect the tides?
The gravity of the moon pulls on the side of the Earth that is facing the moon, which causes high tide on that side and the opposite side. This causes low tides on the other sides of the Earth.
How does gravity affect the tides?
4,3

18. To increase friction you will use a rough surface (salt, sand), and/or add mass. Example: salt ice so that you can walk and not fall on your face
How can you increase friction? What is an example of when you would need to increase friction?
4,4

19. The net force is 40 Newtons to the right.
In a game of tug of war team A pulls the rope with a
force of 120 Newtons to the right. Team B pulls the rope
to the left with 80 Newtons to the left. What is the net
force being applied on the rope and in which direction?
5,1

20. List the four types of friction and provide an example for each.
1. static 2. sliding 3. rolling 4. fluid
List the four types of friction and
provide an example for each.
5,2

21. How does gravity affect the the alignment of the planets?
The gravity of the sun and the gravity of the planets keep one another in alignment, since their mass is so huge, and gravity depends on mass.
How does gravity affect the the
alignment of the planets?
5,3

22. Mass depends on the amount of matter in an object.
What is mass dependent on?
5,4