Question

A string is used to pull a block of mass m vertically up by a distance h at a constant acceleration g/4. The work done by the tension in the string is?

Answer 1

Tension = m(g + a)
= m(g + g/4)
= 5mg/4

Work done = Tension × Displacement
= 5mg/4 × h
= 5mgh/4

Answer 2

t = m(g+a)
t = m(g+g/4)
t = 5mg/4
w = t x distance
w = 5mg/4 x h
w = 5/4 mgh