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Question
A person is standing on a truck moving with a constant velocity of 14.7 m/s on a horizontal road. The man throws a ball in such a way that it returns to the truck after the truck has moved 58.8 m. Find the speed and the angle of projection as seen from the truck .
Solution
Given:
Velocity of the truck = 14.7 m/s
Distance covered by the truck when the ball returns again to the truck = 58.8 m
Therefore, we can say that the time taken by the truck to cover 58.8 m distance is equal to the time of the flight of the truck.
Time in which the truck has moved the distance of 58.8 m:
T = 4 s
Time taken to reach the maximum height when the final velocity v = 0:
∴ v = u − at
⇒ 0 = u + 9.8 × 2
⇒ u = 19.6 m/s
19.6 m/s is the initial velocity with which the ball is thrown upwards.
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