A machine has a velocity ratio of 4. if it requires 800 N to overcome a load of 1600 N,what is the efficiency of the machine?

Answer Details

The efficiency of a machine is the ratio of output work to input work. In this case, the load is 1600 N and it requires 800 N to overcome it. So, the input work is 800 N × distance moved by effort. The output work is 1600 N × distance moved by load.
Velocity ratio is the ratio of the distance moved by effort to the distance moved by load.
Velocity Ratio = distance moved by effort / distance moved by load
Velocity Ratio = 4
distance moved by effort = 4 × distance moved by load
Input work = force × distance moved by effort
Input work = 800 N × 4 × distance moved by load
Output work = force × distance moved by load
Output work = 1600 N × distance moved by load
Efficiency = Output work / Input work
Efficiency = (1600 N × distance moved by load) / (800 N × 4 × distance moved by load)
Efficiency = 0.5 = 50%
Therefore, the efficiency of the machine is 50%. Option (B) is the correct answer.