Phy 201
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13 seed Q
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 initial velocity in the vertical direction is 20cm/sec, but it will have an acceleration of 9.8m/s. Its displacement is 120cm.
• What therefore are its final velocity, displacement, change in velocity and average velocity in the vertical direction?
The displacement once again will be 120cm and we can find final velocity using the formula vf^2=vo^2+2a(‘ds) which means that vf^2= 20cm/s^2+2(980cm/sec)(120cm) which would give a final velocity of 485cm/sec. This makes the change in velocity 465cm/sec and the average velocity 252.5cm/sec.
• 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 balls initial velocity in the horizontal direction is 80cm/sec. The balls acceleration will be the same as it was on the horizontal surface but will lose the force of friction. I am not sure how you would exactally determine acceleration and wouldn’t positional change be different horizontally? It is moving at an angle so it would be different right?
• What therefore are its displacement, final velocity, average velocity and change in velocity in the horizontal direction during this interval?
I would need the above information to find this, but I could if I knew what the acceleration of the object was and if I would just use the 120cm for the positional change.
• After the instant of impact with the floor, can we expect that the ball will be uniformly accelerated?
No, the ball’s acceleration will change due to frictional changes and will no longer be falling vertically.
• Why does this analysis stop at the instant of impact with the floor?
Once the ball hits the floor it will continue moving horizontally but it won’t keep moving vertically
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20 mins
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