Question

If a `2 kg` object is being constantly accelerated from `0m/s` to `15 m/s` over `6s`, how much power is being applied at `t= 2`?

Answer 1

The power is `=25W`

Explanation:

The mass of the object is `m=2kg`

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

The final velocity is `v=15ms^-1`

The time is `t=6s`

Apply the equation of motion

`v=u+at`

To calculate the acceleration

`a=(v-u)/t=(15-0)/6=2.5ms^-2`

According to Newton's Second Law

`F=ma`

The force is

`F=2*2.5=5N`

The velocity when `t=2` is given by the equation

`v=u+at=0+2*2.5=5ms^-1`

The power is

`P=Fv=5*5=25W`