Question

3. A 20 kg lawnmower is pushed by its handle, which makes a 40 degree angle with the horizontal. What

work is done by the person pushing the mower if she pushes along the handle with 30 N of force, the lawn is 20
m long, and requires 30 passes to finish?

Answer 1

13788 J is required to finish the work.

Step-by-step explanation:

Given that,

Mass of lawnmower is 20 kg

Force = 30 N

`\text { Angle }(\theta)=40^(\circ)`

Displacement ( distance moved )= 20m

The force of 30N is applied along the direction of motion and was applied for the whole 20 m.

The formula of work done for one pass is

`\text { Work done }=\text { force } * \text { displacement } * \cos \theta`

Substituting the given data into the formula,

`W=30 * 20 * \cos 40^(\circ)`

`\mathrm{W}=600 * \cos 40^(\circ)`

`\mathrm{W}=600 * 0.766`

W = 459.6 J

Work done for one pass = 459.6J

Now, work done for 30 passes is calculated by multiplying the work done for one pass into 30.

`\text { Then the work done for } 30 \text { passes is } 459.61 * 30=13788 \mathrm{J}`

Work is done by the person pushing the mower to finish the work is 13788 J.