Question

A 20-kg object connected to a spring is oscillating on a frictionless tabletop. At a particular moment, the object's speed is 5.0 m/s and the spring potential energy is 150 J. What will be the object's speed (in m/s) when the potential energy is 300 J?

A) 5.67

B) 8.23

C) 10.00

D) 6.89

E) 3.16

Answer 1

Total mechanical energy of the spring-object system is the sum of kinetic energy of the object and the potential energy of the spring

At the particular moment when speed of the object is v=5m/s, the potential energy U=150J, the mechanical energy of the system is

Given the tabletop is frictionless, there is no loss of energy. The sum of kinetic and potential energy of the object-spring is system is always 400J. We want to find object's speed when the potential energy is 300J