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Q2.8: NCERT Physics - Part 1 MOTION IN A STRAIGHT LINE 2.8 Solution: A ball is dropped from a height of 90 m on a floor. At each…
A ball is dropped from a height of 90 m on a floor. At each collision with the floor, the ball loses one tenth of its speed. Plot the speed-time graph of its motion between t = 0 to 12 s.
Step-by-Step Verified Solution
**Answer:** The graph is a series of straight lines with decreasing slopes after each bounce.
**Step-by-Step Explanation:**
First fall: v = �(2gh) = �(2 _ 9.8 _ 90) = 42 m/s. Time = v/g = 4.28 s.
After bounce: speed = 0.9 _ 42 = 37.8 m/s. Time to rise and fall = 2 _ 37.8/9.8 = 7.71 s.
After second bounce: speed = 0.9 _ 37.8 = 34.0 m/s.
The speed-time graph shows straight lines decreasing after each bounce.
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