Its asking for velocity

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?

Explain what will happen if decomposers were apsent from a forest ecoysystem.

Smallest intensity of a stimulus that you can detect 50 percent of the time is