1. A pulley system has efficiency 60%. Calculate mechanical advantage to make its velocity ratio 6 .How much amount of effort is required to lift 3000 N load by using this pulley system?​

Efficiency = Mechanical advantage / Velocity Ratio:
0.60 = M.A./6
MA = 0.6 * 6 = 3.6
The mechanical advantage is 3.6
Mechanical advantage = Force out / Force in
3.6 = 3000/ Force in
Force in = 3000/3.6
Force in = 833.33 N
Answer: 833.33N