Chapter 6, Problem 6P

Estimate the work you do to mow a lawn 10 m by 20 m with a 50-cm-wide mower. Assume you push with a force of about 15 N.

To determine

Work to mow the lawn.

Answer to Problem 6P

Solution:

6000 J

Explanation of Solution

We know that the mower can cover the 0.5 m distance in one pass. So, to cover the total 200 m² area we can divide the total lawn area by the mower one pass distance.

Given:

Lawn area, a=10m×20m = 200 m².Mower width, w= 50 cm= 0.5 m. Push force, F=15 N

Formula used:

$W=Fd$

Where “F” is the Push force

“W” is the work done

“d” is the distance cover by the mower.

Calculation:

The mower can cover 0.5 m distance in one pass so as to cover the total lawn area which is 200 m² the total area can be divided by the mower distance.

So we are getting mower total distance, d = 400 m.

Work done cutting the lawn

$W=Fd$

$W=15\times 400$

$W=6000 \text{ J}$