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

The power is `=9.375W`

Explanation:

Mass of the object is `m=2kg`

To calculate the acceleration, apply the equation of motion

`v=u+at`

The acceleration is

`a=(v-u)/t=(15-0)/12=1.25ms^-2`

According to Newton's Second Law of Motion

`F=ma`

The force is

`F=2*1.25=2.5N`

The speed at `t=3s` is

`v=0+1.25*3=3.75ms^-1`

The power is

`P=Fv=2.5*3.75=9.375W`