Question

If a `2 kg` object is constantly accelerated from `0m/s` to `16 m/s` over `9 s`, how much power musy be applied at `t= 1`?

Answer 1

The power needed is `6 26/81W` or about 6.32W

Explanation:

When a force `F` is applied to an object moving at velocity `v`parallel to the force, the power needed is `P=Fv`.

The acceleration is `a=(Deltav)/(Deltat)=(16m/s-0m/s)/(9s-0s)=16/9m/s^2`

According to Newton's 2nd law the force is `F=ma=2kg*16/9m/s^2=32/9N`

Velocity at `t=1s` is `v=at=16/9m/s^2*1s=16/9m/s` and the power at this moment is `P=Fv=32/9N*16/9m/s=512/81W=6 26/81W~~6.32W`