Question

A girl playing tug-of-war with her dog pulls the dog a distance of 8.0m by exerting a force at an angle of 18° with the horizontal. If the amount of work the girl does in pulling the dog is 190 J, what is the magnitude of the force?

Answer 1

Answer:

25 N

Explanation:

Work is a product of force and perpendicular distance moved.

W=Fd where F is force exerted and d is perpendicular distance.

However, for this case, the distance is inclined hence resolving it to perpendicular so that it be along x-axis we have distance as $dcos\theta$

Therefore, $W=Fdcos\theta$

Making F the subject of the formula then

$F=\frac {W}{dcos\theta}$ where $\theta$ is the angle of inclination. Substituting 190 J for W then 18 degrees for $\theta$ and 8 m for d then

$F=\frac {190}{8cos18^{\circ}}\approx 25N$