Final answer:
The efficiency of a machine with an input work of 150J and an output work of 90J is 60%, calculated using the formula % Efficiency = (Output work / Input work) × 100.
Step-by-step explanation:
To calculate the efficiency of a machine, you can use the formula:
% Efficiency = (Output work / Input work) × 100.
In this case, the input work (Wi) is 150J, and the output work (Wo) is 90J. So, the efficiency calculation is:
% Efficiency = (90J / 150J) × 100
% Efficiency = 0.6 × 100
% Efficiency = 60%
Therefore, the efficiency of the machine is 60%. This means that 60% of the input energy is converted into useful output work, while the rest is likely lost due to elements such as friction and heat.