Question

If s=t³-6t²+9t.find velocity at 2sec accl at 3 sec. the time when body is a rest and the time when body is moving in negative direction.

Answer 1

Answer:

velocity at 2 sec is - 3 m/s, Acceleration at 3 sec is 6 m/sec^2

Explanation:

We know that the instantaneous velocity is obtained by differentiating s = t^3 - 6t^2 + 9t with respect to time after differentiation you will get the expression

V=ds/dt = 3t^2 - 12t + 9........(1)

Put t= 2 sec in equation (1)

You get velocity as -3mlsec.Now we know that acceleration

a = dv/dt now differentiate the expression of velocity obtained in equation (1) with respect to time.After differentiation the expression of acceleration is 6t - 12........(2)

Now put t=3sec in equation (2) acceleration obtained is 6 m/sec^2.

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