The 100kg mass (1000 newton weight) is now effectively supported by two sections of the same rope (the two strands on the left) instead of just one (ignoring the loose end of the rope you’re pulling with), and this means you can lift it by pulling with a force of just 500 newtons—half as much!

Categorized as a simple machine, a pulley is used to reduce the amount of force needed to lift a load. It basically consists of a grooved wheel mounted on an axle or shaft and a rope or belt that runs within the groove. The three different pulley parts are a wheel, an axle, and a rope.

A pulley is a wheel that carries a flexible rope, cord, cable, chain, or belt on its rim. Pulleys are used singly or in combination to transmit energy and motion. Pulleys with grooved rims are called sheaves.

For a given frictional torque at the axle, the difference in tensions (pull side minus load side) can be smaller because the larger radius gives it greater moment. Equivalently, for a given movement of the rope, the larger pulley turns through a smaller angle, so less work is done against the frictional torque.

You would need the specifications of the pulley: radius and mass distribution to allow the calculation of the pulley’s moment of inertia. You can say that as the pulley mass increases, the acceleration of the object decreases.

Mass of the pulley plays insignificant role because they are generally of negligible mass compared to the mass lifted. But if it is of much larger mass than it will definitely affect the max tension in the string because than the force required to lif t a body will also have to overcome the inertia of the pulley also .

Think about what the system will do. If the system is released from rest, the heavy mass will accelerate down, the lighter one will accelerate up, and the pulley will have a clockwise angular acceleration.