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A particle moves in a straight line with non-uniform speed. Its displacement-time or speed-time graph over the interval 0 to 4 s gives areas corresponding to distances: 1 m in the first 1 s, 0.5 m from 1 to 2 s, 0.5 m from 2 to 3 s, and 1 m from 3 to 4 s. Find the average speed (in m/s) from 0 s to 4 s.
- 0.75
- 1
- 1.25
- 0.5
Correct answer: 0.75
Solution
From the speed-time graph (or displacement-time graph), the total distance covered in 4 s can be read off. If the answer is 0.75 m/s, total distance = 0.75 * 4 = 3 m. This is consistent with a graph where the particle covers, say, 1 m in 0-1 s, 0.5 m in 1-2 s, 0.5 m in 2-3 s, and 1 m in 3-4 s, totalling 3 m. Average speed = 3/4 = 0.75 m/s.
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