Question

A man pushes a lawnmower with a force of 170 N at an angle of 37° down from the horizontal. The lawn is 12.0 m wide and requires 16 complete trips across and back. How much work does he do?

Answer 1

Answer on Question #42816, Physics, Mechanics | Kinematics | Dynamics

A man pushes a lawnmower with a force of $170 \, \text{N}$ at an angle of $37{}^\circ$ down from the horizontal. The lawn is $12.0 \, \text{m}$ wide and requires 16 complete trips across and back. How much work does he do?

Solution:

Given:

$F = 170\mathrm{N}$

$\theta = 37{}^{\circ}$

$s = 12\mathrm{m}$

$N = 16$

In order to accomplish work on an object there must be a force exerted on the object and it must move in the direction of the force.

$$W o r k = F \cdot \cos \theta \cdot d$$

where $d$ is distance.

The distance $d$ is

$$d = N s = 1 6 \cdot 1 2 = 1 9 2 \mathrm {m}$$

Thus,

$$W o r k = 1 7 0 \cdot \cos 3 7 {}^ {\circ} \cdot 1 9 2 = 2 6 0 6 7 \mathrm {J} \approx 2 6 \mathrm {k J}$$

Answer. $W = 26067$ J.

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