1. 8th Grade
Forces and Motion

2. Forces
Speed, Velocity
And
Acceleration
Newton’s
Laws
vocabulary
Mix Up 10 10 10 10 10 20 20 20 20 20 30 30 30 30 30 40 40 40 40 40 50 50 50 50 50

3. Return to Question Board
10 points
In the picture above, a boy is trying to pull a dog on a leash, but the dog and the boy are moving in the same direction. Which of the following best describes the forces in this situation?
F The forces are balanced, and the net force is zero.
G The forces are unbalanced, and the boy’s force is
greater.
H The forces are unbalanced, and the dog’s force is
J The forces are balanced, and the dog is stronger
than the boy
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10 points
A N S W E R:
H The forces are unbalanced, and the dog’s force is greater.
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20 points
Unbalance forces cause a change in an
objects______________.
A shape
B speed, shape, and direction
C color and direction
D velocity
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6. A N S W E R: B speed, shape, and direction
20 points
A N S W E R: B speed, shape, and direction
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30 points
A sailboat comes with an outboard motor which applies a force of 75 N. A gust of wind applies a force of 25 N to the sailboat. What is the net force and direction of the movement if the water exerts a force of 50 N?
F 50 N to the Right
G 50 N to the Left
H 150 N to the Right
J 150 N to the Left
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A N S W E R: F 50 N to the left
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40 points
According to the diagram shown,
F the forces acting on the helicopter are unbalanced.
G the helicopter is speeding up due to unbalanced forces
H the helicopter is slowing down
J the helicopter is not changing speed or direction.
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40 points
A N S W E R:
J the helicopter is not changing speed or direction.
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50 points
An unhappy individual is trying to slide a 100 kg desk across a wood floor. He pushes with a force of 800 N but the desk does not move. One can conclude that the force of friction is:
A    exactly 800 N
B    more than 980 N
C    more than 800 N
D    exactly 980 N
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50 points
A N S W E R:
A    exactly 800 N
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13. A pitcher through a fast ball at 75 mph. This is an example of _____.
10 points
A pitcher through a fast ball at 75 mph. This is an example of _____.
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14. Return to Question Board
10 points
A N S W E R: speed
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20 points
The suspect fled from the police on foot at 2 miles per hour east on Wallisville. This is an
example of_____
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20 points
A N S W E R: velocity
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17. Return to Question Board
30 points
All are examples of acceleration except----.
A) a car making circles in the parking lot is
B) A bicycle stopping and slowing down at an
intersection
C)A student typing 30 words per minute on the
computer
D) A student running north on a winding trail.
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30 points
A N S W E R:
C)A student typing 30 words per minute on the
computer
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19. Return to Question Board
40 points
A car that begins to move after a stoplight turns green is an example____.
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20. Return to Question Board
40 points
A N S W E R:
acceleration
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21. Return to Question Board
50 points
Which example differentiates between speed and velocity?
A An airplane speeds up to take off and slows down to land.
B A car driving 50 mph down the highway, as a train traveling east moves 100 mph.
C A marathon runner jogs 30 miles in an hour, whereas a sprinter runs 100 meters in 13 seconds.
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50 points
A N S W E R:
B A car driving 50 mph down the highway, as a train traveling east moves 100 mph.
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23. Return to Question Board
10 points
The illustrations show soccer balls of different masses being kicked with equal force.
Which ball will have the greatest acceleration?
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24. Return to Question Board
10 points
A N S W E R: A
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25. Return to Question Board
20 points
According to Newton’s 3rd Law, when a hammer
strikes and exerts a force on a nail, the nail__.
A creates a balanced force
B disappears into the wood
C moves at a constant speed
D exerts an equal and opposite force back on the
hammer
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A N S W E R:
D exerts an equal and opposite force back on the
hammer
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27. Return to Question Board
30 points
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30 points
A N S W E R: D
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29. Return to Question Board
40 points
A baseball is thrown by an astronaut standing on the surface of the moon. It continues to move in the direction it is thrown until it gets caught up in Earth’s gravitational pull. What primarily allows it to travel so far? A lack of air which is a source of gravity B lack of air which is a source of acceleration C lack of air which is a source of friction D lack of air which is a source of inertia
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40 points
A N S W E R:
C lack of air which is a source of friction
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31. Return to Question Board
50 points
A book is sitting on a dashboard of a car that's stopped at a traffic light. As the car starts to move forward, the book slides off the dashboard. Which choice best explains why the book moved?
A There was grease on the dashboard.
B The car was moving forward, therefore when it stopped the book continued in the forward motion due to inertia.
C A supernatural force took over.
D Air resistance made the book move backward.
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50 points
A N S W E R: B The car was moving forward, therefore when it stopped the book continued in the forward motion due to inertia
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33. Return to Question Board
10 points
The measure of distance divided by time is
______________.
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34. Return to Question Board
10 points
A N S W E R:
speed
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35. Return to Question Board
20 points
An object’s tendency to resistance a change in motion is________.
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20 points
A N S W E R:
inertia
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37. A change in velocity is_______.
30 points
A change in velocity is_______.
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38. Return to Question Board
30 points
A N S W E R:
acceleration
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39. _________is the speed and direction an object is moving.
40 points
_________is the speed and direction an object is moving.
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40. Return to Question Board
40 points
A N S W E R:
velocity
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41. Return to Question Board
50 points
Unit of measurement
for force
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42. Return to Question Board
50 points
A N S W E R:
Newton
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43. Return to Question Board
10 points
A force is anything that can put matter in motion. Objects exert forces on each other. For example, when you sit on a chair, you exert a force on the chair and the chair exerts a force back on you.
What exert mean?
A it is a synonym for inertia
B to apply a force
C cause a change
D stop
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44. Return to Question Board
10 points
A N S W E R:
B to apply a force
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45. Return to Question Board
20 points
Every force has two parts. What are the part? A) push or pull B) speed and direction C) direction and acceleration D) magnitude, or strength and direction
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20 points
A N S W E R:
D) magnitude, or strength and direction
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47. Return to Question Board
30 points
Which of the following objects is most likely to move to the right, ?
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48. Return to Question Board
30 points
A N S W E R: B
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49. Return to Question Board
40 points
___________is a force that opposes motion between two surfaces that are in contact with each other; they rub against each other in opposite directions
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50. Return to Question Board
40 points
A N S W E R:
friction
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51. Return to Question Board
50 points
Whenever the surfaces of two objects rub together, a friction force is generated that acts on both objects and opposes their relative motion. This is true even if one (or both) of the objects is a fluid (a gas or liquid, such as air or water). When the fluid in question is air, the friction force generated is called air resistance or wind resistance. What does the word resistance mean?
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52. To oppose, opposite or against Return to Question Board
50 points
A N S W E R:
To oppose, opposite or against
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