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plz here is Phy qs needs to be solved A jogger runs around a circular track of 3

ID: 1589725 • Letter: P

Question

plz here is Phy qs needs to be solved

A jogger runs around a circular track of 30 m radius shown in the figure at the right. She runs at a constant speed in a clockwise direction and completes one lap in 40 seconds. Compare the directions and magnitudes of her instantaneous velocity at A, her instantaneous velocity at C, and her average velocity going from A to C. If the runner completes exactly one lap what is her average speed? Her average velocity? Explain your answer. Is the magnitude of her average velocity from A to B bigger, smaller or equal to the magnitude of her average velocity from A to C? Explain your reasoning. For this example, which do you think is more relevant: average speed or average velocity? For whichever one you chose can you think of an example in which the other one is more relevant or interesting?

Explanation / Answer

time it take to complete one lap = 40 sec

speed = distance / time

speed = 2 * pi * radius / 40

speed = 2 * pi * 30 / 40

speed = 4.712 m/s

since speed is constant everywhere so

instantaneous velocity at A = 4.712 m/s toward +y axis

instantaneous velocity at C = 4.712 m/s toward -y axis

average velocity between A and C = total displacement / total time

average velocity between A and C = pi * radius / 20

average velocity between A and C = pi * 30 / 20

average velocity between A and C = 4.712 m/s

on completion of one lap

average speed = total distance / total time

average speed = 2 * pi * radius / 40

average speed = 2 * pi * 30 / 40

average speed = 4.712 m/s

average velocity = total displacement / total time

total displacement will be 0 since starting and ending points are same

average velocity = 0 / 40

average velocity = 0 m/s