You and a friend are on a swing set and her swing is slightly longer than yours. If you both start swinging at the same time, from the same height, where will she be after you have completed one complete swing back and forth? a. She will still be at the same height as you.
b. She will be slightly higher than you.
c. She will be slightly lower than you but moving downward away from you.
d. She will be slightly lower than you but moving upward toward you.

d. She will be slightly lower than you but moving upward toward you.

Explanation:

Since your swing is slightly shorter than your friend's swing, then you will have more angular speed than your friend. Angular speed increases with a decrease in radius. The closer the body is to the center, the faster the body swings. By the time you would have completed one complete swing back and forth, your friend will just be moving towards you, and she will be slightly lower than you but moving upwards towards you. This principle is the same reason gymnasts pull their limbs closer to their body when they need to swing faster.

acceleration = (change in speed) / (time for the change)

change in speed = (20-120)= -100 m/s.

1.5 min = 90 sec

acceleration = -100/90 = -1.11 m/s^2.

we don't care about the 150kg or the 2,500 meters. they don't make any difference.

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