What is the main idea of quantum psychics?

Apulley system is used to lift a 2,000 newton engine up a distance of 3 meters. the operator must apply a force of 250 newtons to the chain of the pulley system to lift the motor. to lift the engine 3 meters, the operator must pull a total of 30 meters of chain through the pulley system. what is the value of di?

A20 cm long spring is attached to a wall. the spring stretches to a length of 22 cm when you pull on it with a force of 100 n. what is the spring constant

An object in mechanical equilibrium is an object