A gardener pushes a lawn roller through a distance of 20 m. If he applies a force of 20 kg weight in a direction inclined at 60 ° to the ground, find the work done by him. $(g = 9.8 m/s^2)$

As we know that,

Work(W) = Force(F) x Displacement(s)

$\mathrm{W} = \mathrm{Fscos\theta }$

Where,

θ is the angle between force and displacement.

From the question we have,

Mass $\left(m\right) = 20 kg$

Acceleration due to gravity $\left(g\right) = 9.8 m/s^2$

Force $\left(F\right) = m\times g = 20\times 9.8 = 196 N$

Displacement(s) = 20 m

θ = 60 ° 

So, the work done is,

$$\begin{gathered} \mathrm{W} = \mathrm{Fscos\theta } \\ = 196\times 20\times \cos 60 ° \\ = 196\times 20\times 0.5= 1960 \mathrm{J} \end{gathered}$$