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A particle travels along a straight path with uniform acceleration. As it covers a distance of 135 m, its speed increases from 10 m s⁻¹ to 20 m s⁻¹ in t seconds. What is the value of t?

1. 10 s
2. 1.8 s
3. 12 s
4. 9 s

Correct answer: 9 s

Solution

The correct option is 9 seconds because, using the equations of motion for uniformly accelerated motion, we can calculate the time taken to cover the distance of 135 m while the speed changes from 10 m/s to 20 m/s. The average speed during this interval is 15 m/s, and using the formula distance = average speed × time, we find that time equals 135 m / 15 m/s, which results in 9 seconds.

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