Question

What is the power required to lift a 4kg chair 2m in 3s?

Answer 1

First, let's calculate the weight force of the chair:

`\begin{gathered} F_w=m\cdot g \\ F_w=4\cdot9.8 \\ F_w=39.2\text{ N} \end{gathered}`

Now, calculating the work done by this force, we have:

`\begin{gathered} W=F_w\cdot d \\ W=39.2\cdot2 \\ W=78.4\text{ J} \end{gathered}`

The power is given by the work divided by the amount of time:

`\begin{gathered} P=(W)/(t) \\ P=(78.4)/(3) \\ P=26.13\text{ W} \end{gathered}`

The power required is 26.13 W, therefore the correct option is the first one.