Question

A man climbs a ladder carrying a concrete block of mass 5 kg. If the ladder makes an angle of 30° to the vertical and is 3 m long,how much work the man does on the block ?

Answer 1

Zero because,
W = Fs
​  = Fs 
 =F(0) = 0    [As the wall does not move the displacement is zero]Zero because,

Answer 2

The man climbs at elevator speed of the vertical ladder.

A concrete block of mass = 5 kg, the angle of the ladder is 30 degree and long with 3 m.  

According to the formula, Work = Fs, F = mg, S =h,

So, F (0) =0. Zero is the answer to this question.