Question

Jay bought a toy car. To make the car move, he must turn a key attached to a spring. Turning the key winds the spring tight. The toy car moves when the key is released and the spring unwinds. What’s the main transformation of energy in this example?

Answer 1

The chemical energy in Jay's body, to kinetic energy in the car

Answer 2

Answer:

Elastic potential energy into kinetic energy

Explanation:

Initially, all the energy is stored in the spring, which is compressed. This energy is called elastic potential energy, and it is equal to

$U=\frac{1}{2}kx^2$

where k is the spring constant and x is the compression of the spring. When the key is turned, the spring is released, and all this energy is converted into kinetic energy, which is the energy due to the motion of the car. The equation that gives this energy is

$K=\frac{1}{2}mv^2$

where m is the mass of the car and v is the speed of the car.