Question

If a `2 kg` object is constantly accelerated from `0m/s` to `15 m/s` over `12s`, how much power musy be applied at `t= 3`?

Answer 1

9.4W

Explanation:

Constant acceleration here denotes a constant force `F.`

To find out the power `P` required, we need to find out `(dW)/(dt)` , the rate of work done with respect to time at `t=3s`. Alternatively, the equation `P=Fv` can be used.

`P=(dW)/(dt)=(d(Fx))/(dt)=F((dx)/(dt))=Fv=mav`

To find `a` , we can use the kinematics equation `a=(v-u)/t`.

`a=(15-0)/12=1.25m/s^2`

To find `v` at `t=3s` , we can use `v=u+at`.

`v=0+(1.25)(3)=3.75m/s`

Therefore, the power required is

#P =mav =(2)(1.25)(3.75) =9.375 =9.4W#