1. Frictional force is the force that opposes the motion of objects as they pass over each other. It is caused by the roughness of surfaces and the interactions between molecules in contact with each other. Frictional force can either help or hinder motion, depending on the circumstances.
2. The efficiency of a machine is a measure of how well it converts input energy into useful work output. It is calculated by dividing the useful work output by the total input energy. Efficiency is always less than 100% because some of the input energy is always lost to factors such as friction, heat, and sound. These losses are unavoidable and result in a decrease in the overall efficiency of the machine. In real-world applications, achieving 100% efficiency is practically impossible due to these inevitable energy losses.
Define frictional force
2
Explain the efficiency of a machine is always less than 100%
1 answer