Question

A foolish man tried to pull out a nail in the wall with a string attached to the head of the nail . The man pulled at an angle of 30° the wall . if the tension in the string is 5N , Calculate the force effective in pulling out the nail .

Explain why the man is foolish

Answer 1

To pull out the nail, the effort must be applied along the axis of the nail. Therefore, the component of the force that acts along the axis is just

$$F_a=F\cos30°=4.3\text{ N}.$$

This is foolish because having the angle he decreases the force that acts on the nail.