(c) What is the mechanical advantage and velocity ratio if the efficiency is 100%?

(d) What will be the mechanical advantage and velocity ratio if the efficiency becomes 50%?

Solution

(c)

According to the question, effort arm is 9cm long and load arm is 5 cm.

Expression for Mechanical advantage is

M.A. = Effort arm / Load arm = 9 cm / 5 cm

Thus, M.A. = 1.8

Expression for relation between mechanical advantage, efficiency and velocity ratio is

M.A. = η × V.R.

where η = 100% = 1

Therefore, M.A.= V.R.

(d) When efficiency decreases, the mechanical advantage decreases, while the velocity ratio remains constant. As a result, when efficiency reaches 50%, M.A. = 0.9 and V.R. = 1.8.