PHY 201
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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, what are the ball's initial velocity, displacement and acceleration in the vertical direction?
The time when the ball left the ramp is the initial velocity, so the initial velocity was 20 cm/s. The displacement is 120 cm. The acceleration is the change in velocity divided by the time it took to make the 120 cm distance. If the balls’ velocity when it hits the floor is going to be zero, so the change in velocity is 20 cm/s. The time it takes is taken from the average velocity, which is -10 cm/s and the displacement 120 cm: 120 cm / 10 cm/s = 12 seconds. So, the acceleration will therefore be: 20 cm/s / 12 s = 1.67 cm/s^2. I do not think this is right, because it would not take 12 seconds for the ball to reach the floor????????
The ball accelerates downward at 980 cm/s^2. It takes only around half a second to fall.
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• What therefore are its final velocity, displacement, change in velocity and average velocity in the vertical direction?
The final velocity is 0 cm/s. The displacement is 120 cm. The change in velocity is 20 cm/s. Then the average velocity would be 10 cm/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 ball’s initial velocity is 0 m/s, because the ball started at rest, assumingly. The final velocity is 80 cm/s, so the change in velocity is 80 cm/s. The average velocity is 40 cm/s. How do u get the clock time, without knowing the displacement?
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• What therefore are its displacement, final velocity, average velocity and change in velocity in the horizontal direction during this interval?
The final velocity is 80 cm/s. The average velocity is 40 cm/s. The change in velocity is 80 cm/s. The displacement is what I do not how to calculate???????
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• After the instant of impact with the floor, can we expect that the ball will be uniformly accelerated?
Yes, because the gravitational force is constant that is pulling the ball down.
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• Why does this analysis stop at the instant of impact with the floor?
The ball is therefore not traveling anymore and is not moving at that point.
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45 minutes
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Solution
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