Question

question 3
a man is cutting the grass using a human - powered lawn mower. he pushes the mower with a force of 45 n directed at an angle of 41° below the horizontal direction. calculate the work that the man does on the mower each time he pushes it 9.1 m across the yard.
310 j
510 j
260 j
410 j
360 j

Explanation:

Step1: Write the formula for work

The formula for work \( W \) is \( W = Fd\cos\theta \), where \( F \) is the force, \( d \) is the displacement, and \( \theta \) is the angle between the force and the displacement.

Step2: Substitute the given values

Given \( F = 45\space N \), \( d = 9.1\space m \), and \( \theta=41^{\circ} \).
So \( W = 45\times9.1\times\cos(41^{\circ}) \).
We know that \( \cos(41^{\circ})\approx0.7547 \).
Then \( W = 45\times9.1\times0.7547\).
First calculate \( 45\times9.1 = 409.5 \).
Then \( W=409.5\times0.7547\approx310\space J \).

Answer:

310 J