Introduction to Newton's Laws in a 9th grade physics class. Inertia/balanced vs. unbalanced forces, force diagrams and system schemas
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Question 1
1.
Inertia is a force which keeps moving objects in motion at a constant velocity.
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Question 2
2.
In a gravity-free environment, it would not require any force to set an object in motion.
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Question 3
3.
The amount of inertia an object has depends on where it is in the universe.
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Question 4
4.
Spaceships can travel at enormous speeds without firing their engines after being launched.
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Question 5
5.
A balance of forces is demonstrated by an object which is slowing to a stop.
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Question 6
6.
It would take an unbalanced force to keep an object in motion.
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Question 7
7.
If an object is constantly accelerating then the forces are balanced.
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Question 8
8.
A free-falling object experiences a balance of forces (before reaching terminal or constant velocity).
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Question 9
9.
Unbalanced forces cause moving objects to come to rest.
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Question 10
10.
If a football is moving upwards and rightwards towards the peak of its trajectory, then there are both rightwards and upwards forces acting upon it.
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Question 11
11.
If an object is at rest then there are no forces acting upon the object.
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Question 12
12.
A pendulum bob is set into its usual back-and-forth periodic motion. You and your good friend Pat, are watching it swing and, after some time (perhaps 10 minutes), the pendulum bob comes to a rest position.
Pat says, “This is explained by the idea of inertia - all objects eventually come to rest.”
Do you agree with Pat’s explanation? If so, say why. If not, say why not. Use the language and vocabulary of Newton’s 1st Law.
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Question 13
13.
Which of the free body diagrams could depict an object moving to the right with a constant speed?
Select all that apply.
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Question 14
14.
Construct free-body diagrams below each description for the instant in time for which they are described. As is always done in free-body diagrams, label the forces according to type and draw the arrows such that their length reflects the magnitude of the force.
Ignore Fair .
1) A hockey puck is gliding to the right at constant velocity. Ignore friction.
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Question 15
15.
Construct free-body diagrams below each description for the instant in time for which they are described. As is always done in free-body diagrams, label the forces according to type and draw the arrows such that their length reflects the magnitude of the force.
Ignore Fair .
2) An object is being pushed rightward across the floor at a constant velocity. Consider friction.
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Question 16
16.
Construct free-body diagrams below each description for the instant in time for which they are described. As is always done in free-body diagrams, label the forces according to type and draw the arrows such that their length reflects the magnitude of the force.
Ignore Fair .
3) A bucket is being lowered by a rope from a frictionless pulley into a well at a constant speed.
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Question 17
17.
Construct free-body diagrams below each description for the instant in time for which they are described. As is always done in free-body diagrams, label the forces according to type and draw the arrows such that their length reflects the magnitude of the force.
Ignore Fair .
4) A football is flying and upwards and rightwards through the air.