Phy 201
Your 'cq_1_03.1' 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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Seed Question: Asst 3 Question 1
The problem:
A ball starts with velocity 0 and accelerates uniformly down a ramp of length 30 cm, covering the distance in 5 seconds.
• What is its average velocity?
answer/question/discussion: ->->->->->->->->->->->-> :
The average velocity is 6 cm/sec
Proof: `dv = Avel * `dt
30 cm = Avel * 5 sec
30 cm / 5 sec = Avel
6 cm/sec = Avel
• If the acceleration of the ball is uniform then its average velocity is equal to the average of its initial and final velocities.
You know its average velocity, and you know the initial velocity is zero.
What therefore must be the final velocity?
answer/question/discussion: ->->->->->->->->->->->-> :
The final velocity is equal to 12 cm/sec
• By how much did its velocity therefore change?
answer/question/discussion: ->->->->->->->->->->->-> :
The velocity changed 6 cm/sec
Proof: change in vel = (Vf – Vo) / 2 = 12 cm/sec/2 = 6 cm/sec
I’m not sure about this answer. This finds the average, but not the change in velocity.
• At what average rate did its velocity change with respect to clock time?
answer/question/discussion: ->->->->->->->->->->->-> :
Vave = (Vf – Vo) / `dt = 12 cm/sec/5 sec = 2.4 cm/sec/sec
The average rate the velocity changed with respect to clock time was
• What would a graph of its velocity vs. clock time look like? Give the best description you can.
answer/question/discussion: ->->->->->->->->->->->-> :
The graph consists of a straight line from point (1 sec, 0 cm/sec) to the point (5 sec,12 cm/sec), with midpoint at (3 sec, 6 cm/sec).
The rise of the graph is 6 cm/sec, and the run of the graph is 5sec. The slope of the graph is 1.2 cm/sec/sec You don't use the midpoint to calculate the slope
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2.5 hours
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Would you please check my answers for how much did its velocity therefore change and average rate the velocity changed with respect to clock time. I'm getting confused.
You've got 90% of this and are one short step away from getting everything straight.
&#Please compare your solutions with the expanded discussion at the link
Solution
Self-critique your solutions, if this is necessary, according to the usual criteria. Insert any revisions, questions, etc. into a copy of this posted document. Mark any insertions with &&&& so they can be easily identified. &#