Question

If a `12 kg` object is constantly accelerated from `0m/s` to `60 m/s` over 8 s, how much power musy be applied at `t=1`?

Answer 1

The power is `=675W`

Explanation:

We apply the equation of motion

`v=u+at`

The initial velocity is `u=0 ms^-1`

The final velocity is `u=60 ms^-1`

The time is `t=8s`

The acceleration is

`a=(v-u)/t=(60-0)/8=7.5ms^-1`

The mass is `=12kg`

According to Newton's Second Law, the force is

`F=ma=12*7.5=90N`

The velocity after `t=1s` is

`v=0+7.5*1=7.5ms^-1`

The power is

`P=Fv=90*7.5=675W`