Question

a student who weighs 556 Newtons climbs the stairway (vertical height of 4.0 m) in 25 s (a) how much work is done (b) what is the power output of the student

Answer 1

Given data:

Weight of the student;

`\begin{gathered} F=mg \\ =556\text{ N} \end{gathered}`

Height;

`h=4.0\text{ m}`

Time;

`t=25\text{ s}`

Part (a)

The work done by the student is given as;

`W=Fh`

Substituting all known values,

`\begin{gathered} W=(556\text{ N})*(4.0\text{ m}) \\ =2224\text{ J} \end{gathered}`

Therefore, the work done by the student is 2224 J.

Part (b)

The power is defined as the rate of doing work. Mathematically,

`P=(W)/(t)`

Substituting alll known values,

`\begin{gathered} P=\frac{2224\text{ J}}{25\text{ s}} \\ =88.96\text{ W} \end{gathered}`

Therefore, the power output of the student is 88.96 W.