Use hooke's law to determine the work done by the variable force in the spring problem. a force of 250 newtons stretches a spring 30 centimeters. how much work is done in stretching the spring from 30 centimeters to 60 centimeters? n-cm

A1000-kg weather rocket is launched straight up. the rocket motor provides a constant acceleration for 16-s, then the motor stops. the rocket altitude 20-s after launch is 510-m. you can ignore any effects of air resistance. a. what was the rocket’s acceleration during the first 16-s? b. what is the rocket’s speed as it passes through a cloud 5100-m above the ground?

Inside of a windmill or a dam is a that is used to transform one type of energy into electrical energy. a. motor b. generator c. transformer d. power pack

What is the increase in density of a medium due to wave travel?