Question

A boy pulls up a bucket of water from a well $80m$ deep. If the mass of the bucket along with water is $20kg$, the amount of work done by the boy is:

[Take $g=10m/s^2$]

• A. $1,60,000J$
• B. $20,000J$
• C. $16,000J$
• D. $2,00,000J$

Answer 1

The correct option is C

$16,000J$

Step 1: Given data

Given that,

Vertical height, $h=80m$

Mass of bucket along with water, $m=20kg$

Acceleration due to gravity, $g=10m/s^2$

Work done, $W=?$ (to be calculated)

Step 2: Calculating the force required to lift the water

Force$\left(F\right)$$=$mass$\left(m\right)$$\times$acceleration due to gravity$\left(g\right)$

$$\begin{gathered} F=m\times g \\ F=20kg\times 10m/s^2=200N \\ \therefore F=200N \end{gathered}$$

Step 3: Calculating the work done

Work done$\left(W\right)$$=$Force$\left(F\right)\times$Displacement$\left(s\right)$

$$\begin{gathered} W=F\times s \\ W=200N\times 80kg=16,000J \\ \therefore W=16,000J \end{gathered}$$

Hence, the correct answer is option (C) i.e. $16,000J$.