Question

A 75 kg firefighter climbs a flight of stairs 28 m high how much work does he do?

Answer 1

Answer: 20580 Joules of work is done by the firefighter.

Explanation:

Work done is defined as the force times distance travelled.

work=$mass\times acceleration\times height$

Given:

mass= 75 kg

acceleration due to gravity = $9.80m/s^2$

h= height = 28 m

Putting in the values we get,

work=$75kg\times 9.80m/s^2\times 28m=20580kgm^2s^{-2}=20580J$

$1kgm^2s^{-2}=1Joule(J)$

Thus 20580 Joules of work is done by the firefighter.

Answer 2

Answer:

He does 20601 J of work

Explanation:

Step 1: Data given

Mass of the firefighter = 75.00 kg

Height of the stairs = 28.00 meters

Step 2: Calculate the work done

The work required = difference between the final potential energy (Uf) and initial potential energy  (Ui)

The work required = Uf - Ui

 ⇒ with  Uf = m*g*h

⇒ with Uf = 75 *9.81 * 28 = 20601 J

 

⇒ Ui = 0 J when we take initial height, h = 0  J

The work required = Uf - Ui

Work required = 20601 - 0 = 20601 J

He does 20601 J of work