If you know the acceleration and time, how can you calculate the average velocity?

Eddy whose mass is 55kg climbs up the 1.50 meter high stairs in 2s.calculate eddy’s power rating

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?

(**i would really appreciate if this was answered soon** ) which pair of quantities includes one quantity that increases as the other decreases during simple harmonic motion?