Motion
What is Motion
A change in an object's position
What is a force?
A push or pull
What is Net Force?
What happens when forces are balanced?
The net force is 0N, there is no change in motion?
What is a reference point?
A student walks from the classroom to the cafeteria. Has the student experienced motion? Explain why.
Yes. The student's position changed over time
What unit is used to measure force?
Newtons (N)
A box has 5N pushing to the right, and 3N pushing to the left. What is the net force, and in what direction will the box move?
2N to the right
<----- 10N 10N ----->
Balanced
You are sitting in a chair. Is the chair moving relative to you?
No
You are sitting in a moving car. Is the person sitting next to you moving relative to the car?
No the person is not moving relative to the car.
Non-contact force
A soccer player kicks a ball with 12N of force to the right. Another player blocks his kick with 4N to the left. What is the net force, and in what direction will the ball move?
8N to the right
Are these forces balanced or unbalanced?
<---- 15N 5N ---->
Unbalanced
A girl is riding her bike past a tree. What could be used as a reference point to determine that she is moving?
The tree
A runner travels 100 meters down a track and then returns to the starting line. Did the runner experience motion even though they ended where they started?
Yes. The runner experienced motion while running on the track.
A student kicks a soccer ball. What type of force is the student applying to the ball?
A contact force
A box has 3 forces acting on it. 10N to the right, 6N to the right, and 8N to the left. What is the net force, and in what direction will the box move?
8N to the right
A book is sitting still on a table. Gravity pulls downward while the table pushes upward with an equal force. Are the forces balanced or unbalanced?
Balanced
A passenger is sitting on a moving train. Relative to another passenger sitting beside them, are they moving?
No, they are stationary relative to each other.
Two students are sitting on a bus. Student A says "We aren't moving." Student B says, "We are moving." Can they both be correct? Explain.
Yes. Motion is relative and depends on the reference point. They are stationary relative to the bus, but moving relative to outside of the bus.
A magnet attracts a paper clip without touching it. What type of force is acting on the paper clip?
A non-contact magnetic force
A sled is being pulled by a kid with 25N to the right. Another kid wants the same sled and pulls it with 10N to the left. What is the net force?
15N to the right
Two forces are working together. One force is pushing the object at 15N, while the other force is also pushing the object in the same direction at 15N. Are these forces balanced or unbalanced?
Unbalanced
A student is sitting on a bus traveling down the road. The student says, "I'm not moving." A person standing on the sidewalk says, "You are moving." Who is correct?
Both. The student is not moving relative to the bus/passenger, but is moving relative to the person on the sidewalk.