Question

in the spring - ball system, what happens to the kinetic energy as the spring compresses? it is destroyed. it is converted into chemical energy. it remains constant. it is converted into elastic potential energy.

Explanation:

According to the conservation of mechanical energy, in an ideal spring - ball system (neglecting non - conservative forces like friction), energy is transformed. Kinetic energy ($K = \frac{1}{2}mv^{2}$) of the ball is not destroyed (as energy cannot be created or destroyed in an isolated system according to the first law of thermodynamics). It is not converted into chemical energy as there is no chemical reaction in a simple spring - ball system. The total mechanical energy $E = K+U$ (where $U$ is the elastic potential energy of the spring, $U=\frac{1}{2}kx^{2}$, $k$ is the spring constant and $x$ is the compression or extension of the spring) is conserved. As the spring compresses ($x$ increases), the velocity of the ball ($v$) decreases. So, the kinetic energy of the ball is converted into elastic potential energy of the spring.

Answer:

It is converted into elastic potential energy.