The pulley arrangements of fig (a) and (b) are identical. The mass of the rope is negligible. In (a) the mass m is lifted up by attaching a mass 2 m to the other end of the rope. In (b) m is lifted up by pulling the other end of the rope with a constant downward force F = 2 mg. Which of the following is correct?

Explanation

In pulling force ,
` F = (2mg- T) = 2 mg - mg = mg `
total mass moved ,
` = m + 2 m = 3 m `
`:.` Acceleration , ` a = a = ("force")/("mass")= (mg)/(3m )= (g)/(3) `
the pulling force ,
`F = (2mg-T) = 2 mg - mg = mg `
mass moved = m
`:.` Acceleration `a (f)/(m) = (mg)/(m) = g ` ,