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course PHY 241
01/13/20128:57 pm
Ramp & Ball
You allowed a ball to roll from rest down a ramp on a tabletop. The lower end of the ramp was positioned so that the ball could roll continuously off the ramp and into free fall. You observed the horizontal range of the falling ball and the distance of fall.
Insert a copy of your data here, along with any previously submitted work you wish to include:
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Time on Ramp distance from table
1.9 seconds 17 cm
1.7 seconds 19.5 cm
1.5 seconds 23.5 cm
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You did trials for three ramps.
Analysis based on projectile motion:
Phy 201 students may assume that the initial projectile velocity is horizontal. University Physics students can do the same as a first approximation, but are expected to also then solve assuming that the initial projectile velocity is parallel to the ramp.
What was the horizontal velocity of the ball as it fell to the floor?
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Assume it takes 0.4 seconds for the ball to reach the floor
Trial one: 42.5 cm/s
Trial two: 48.75 cm/s
Trial three: 58.75 cm/s
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What was the final velocity for each ramp slope?
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31.58 cm/s
33.29 cm/s
40 cm/s
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These look like the average velocities of the ball on the ramp, not the final velocities.
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Based on your result and the length of the ramp, what would have been the acceleration of the ball on the ramp?
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Length of ramp = 61 cm
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Graph acceleration vs. ramp slope and find the slope of this graph.
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You don't appear to have given the accelerations.
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You also don't appear to have reported the height of the raised end of the ramp. You need this to get the slope of the ramp, which is required in order to construct the specified graph.
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What do you think is the percent uncertainty in your measurement of the horizontal distance traveled by the ball from the end of the ramp to the floor?
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as we were estimating the time it took, I think there may be around a 20% chance.
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The horizontal distance was observed without reference to the time required for the ball to roll down the ramp.
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What do you think is the percent uncertainty in your measurement of the vertical distance traveled by the ball from the end of the ramp to the floor?
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0. It was actually measured
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You can't measure any quantity without come uncertainty.
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What do you think is the percent uncertainty in your measurement of the distance traveled by the ball from release to the end of the ramp?
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roughly 5%. I timed it with a stopwatch.
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What therefore do you think is the percent uncertainty in each of the following quantities, as you have calculated them?
• the time required to fall to the floor
• the horizontal velocity of the ball during its fall
• the acceleration of the ball on the ramp
• the slope of your graph of acceleration vs. ramp slope
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Analysis based on timing:
Based on the time down the ramp and the distance the ball traveled from rest as it accelerated down the ramp, what was the acceleration on each ramp, and what is the slope of the graph of acceleration vs. ramp slope?
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1.9 seconds, 61 cm: 32.105 cm/s
1.7 seconds, 61 cm: 35.882 cm/s
1.5 seconds, 61 cm: 40.667 cm/s
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These appear to be average velocities, not accelerations.
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What do you think is the percent uncertainty in your measurement of the time required to travel down the ramp?
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roughly 2% or 3%, I used a stopwatch
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For each ramp:
What was the change in the gravitational PE of the ball? You may assume a 70 gram mass.
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What velocity would have been attained if all the lost PE went into translational KE?
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University Physics students: Account for the difference between the loss of gravitational PE and the translational KE which corresponds to your results. Use your results to find the acceleration of gravity.
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