Question

A man climbs a ladder carrying a hammer of mass 0.5kg.If the ladder makes an angle of 30 with the vertical and is 3m long, How much work does the man do on the hammer?

Answer 1

The work done against the gravitational force is:

$$W = mgh$$

where $m = 0.5 kg$ is the mass of the hummer, $g = 9.81 m/s^2$ is gravitational acceleration and $h$ is the difference between the final and initial levels. From the figure above:

$$h = 3\cos{30\degree} = \dfrac{3\sqrt3}{2} m$$

Thus, the work will be:

$$W = 0.5\cdot 9.81\cdot \dfrac{3\sqrt3}{2}\approx12.74 J$$

Answer. 12.74 J.