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Phy 201
Your 'cq_1_13.1' 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 ball rolls off the end of an incline with a vertical velocity of 20 cm/s downward, and a horizontal velocity of 80 cm/s. The ball falls freely to the floor 120 cm below.
For the interval between the end of the ramp and the floor, hat are the ball's initial velocity, displacement and acceleration in the vertical direction?
The balls initial vertical velocity is 20cm/s, vertical displacement 120cm, and vertical acceleration is 980cm/s^2.
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What therefore are its final velocity, displacement, change in velocity and average velocity in the vertical direction?
Displacement= 120cm
Vf2=20cm2/s2+2(980cm/s2*120cm)
Vf2=20cm2/s2+235200cm2/s2
Vf2=235220cm2/s2
Vf= 485cm/s downward
Change in velocity= 485cm/s-20cm/s= 465cm/s
Average velocity = (20cm/s+485cm/s)/2 = 252cm/s
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What are the ball's acceleration and initial velocity in the horizontal direction, and what is the change in clock time, during this interval?
The initial velocity in the horizontal direction is 80cm/s.
Change clock time= change velocity(vert)/acceleration(vert)
Change clock time= 465cm/s / 980cm/s^2= 0.474seconds
Acceleration(horizontal)= 0cm/s2 because after the ball leaves the end of the ramp, there is no force acting on it the horizontal direction until it contacts the floor.
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What therefore are its displacement, final velocity, average velocity and change in velocity in the horizontal direction during this interval?
Change velocity= 0cm/s since there is no acceleration horizontal.
final velocity= 80cm/s
Average velocity= 80cm/s since there is no change in velocity.
Displacement= (80cm/s) * 0.474seconds= 38cm
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After the instant of impact with the floor, can we expect that the ball will be uniformly accelerated?
Yes, the ball will begin to slow down at a uniform rate after contacting the floor.
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Why does this analysis stop at the instant of impact with the floor?
It stops because friction will be the force that slows the ball down on the floor.
@& During the fall the ball experiences a nice steady gravitational force and as a result accelerates uniformly.
The forces it experiences when contacting the floor are complicated and not uniform. *@
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20 minutes
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@& Very sell done. See my note near the end, but no revision is necessary.
Keep up the good work.*@