Machines require a power source, such as electricity, fuel, or human effort, to perform their intended functions. They also often require maintenance and lubrication for optimal performance.

Examples of machines include cars, trucks, trains, airplanes, cranes, washing machines, and refrigerators, among others.

Animals may jump, run, fight, seek food, find shelter, or flee from predators. Some animals are also trained to perform tasks like lifting weights, carrying loads, or pulling carts.

Work, energy, and power are fundamental concepts that help us understand how energy is transferred and transformed to perform various activities. In living beings, these concepts elucidate how food energy is converted into mechanical work, chemical energy, and heat to ...

Strenuous activities demand more energy because they involve increased muscle work, higher metabolic rates, and greater expenditure of stored energy reserves to sustain prolonged physical effort.