Which of the following is an example of a simple machine?

A pulley is a classic example of a simple machine because it consists of a wheel on an axle or shaft that is designed to support movement and change the direction of force. By using a rope or cable over the wheel, a pulley allows a user to lift heavy loads with less effort compared to lifting them directly. This mechanical advantage arises from redistributing the work needed to lift an object, thereby making it easier to move heavy items vertically.

In contrast, a forklift and an elevator are more complex machines that utilize multiple simple machines, including pulleys in their operation, but they themselves are not classified as simple machines. A computer is a sophisticated electronic device that does not fit the definition of a simple machine, as it does not facilitate mechanical work through basic mechanical principles. Understanding simple machines like the pulley is essential as they are foundational tools that have been utilized for centuries to ease the burden of lifting and moving heavy objects.