Question

A 0.40-kg mass attached to a spring is pulled back horizontally across a table so that the potential energy of the system is increased
from zero to 160 J. Ignoring friction, what is the kinetic energy of the system after the mass is released and has moved to a point where
the potential energy has decreased to 80 J?
The kinetic energy of the system after the mass is released and has moved to a point where the potential energy has decreased to
80 J is

Answer 1

Answer:

KE=80 Joules

Explanation:

Using the conservation of energy, E1=E2. In this case, the object starts off with 160 joules of energy. In E2, 80 joules of energy are stored in potential energy. The remaining energy must have been stored as Kinetic energy as in this case, there is no friction to take away any of the energy as heat. Mathematically, this comes out as E1=E2, 160 Joules= KE+80 Joules(PE). Solving for KE gives 80 joules.