phy121
Your 'cq_1_18.1' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
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A child in a slowly moving car tosses a ball upward. It rises to a point below the roof of the car and falls back down,
at which point the child catches it. During this time the car neither speeds up nor slows down, and does not change
direction.
What force(s) act on the ball between the instant of its release and the instant at which it is caught? You can ignore air
resistance.
The force of gravity is the only force acting on the ball. Since the car does not speed up or slow down, F = m * a says that there is no force from the car.
What happens to the speed of the ball between release and catch? Describe in some detail; a graph of speed vs. clock time
would also be appropriate.
The ball decelerates after release to the peak of its height where it stops and then starts accelerating downward.
Describe the path of the ball as it would be observed by someone standing along the side of the road.
It would have a simliar y-axis movement, but due to its x-axis velocity via the car, it would appear to be an arch.
How would the path differ if the child was coasting along on a bicycle? What if the kid didn't bother to catch the ball?
(You know nothing about what happens after the ball makes contact with the ground, so there's no point in addressing
anything that might happen after that point).
If he was coasting along on a bicycle, the ball would, due to air resistance, slow down on the x-axis when released and land behind the boy.
Since (if) he didn't catch the ball, it would continue to acclerate downward after its peak height until it hits the ground.
What if the child drops the ball from the (inside) roof of the car to the floor? For the interval between roof and floor,
how will the speed of the ball change? What will be the acceleration of the ball? (You know nothing about what happens
after the ball makes contact with the floor, so there's no point in addressing anything that might happen after that point).
The ball would simply accelerate to the floor in what would appear to be a straight line in the car.
It will increase until it hits the floor.
9.8m/s/s
What if the child holds the ball out of an open window and drops it. If the ball is dense (e.g., a steel ball) and the car
isn't moving very fast, air resistance will have little effect. Describe the motion of the ball as seen by the child.
Describe the motion of the ball as seen by an observer by the side of the road. (You know nothing about what happens after
the ball makes contact with the ground, so there's no point in addressing anything that might happen after that point).
The ball will accelerate on the y-axis twards the ground, where it will be decelerating on the x-axis until it hits the ground. Similar to the ball of the end of a ramp projectile experiments.
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10min
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Please let me know if you have any questions related to this orientation assignment.