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Question:

An object, moving with a speed of 6.25 m/s, is decelerated at a rate given by dv/dt = -6.5√v, where v is the instantaneous speed. The time taken by the object to come to rest would be?

1 s

4 s

8 s

2 s

Solution:

∫₀⁶·²⁵ dv/√v = -6.5 ∫₀ᵗ dt
By calculating this we get,
∴t = 2s