Answer: C: 40 Joules
Explanation:
This can be calculated by using the conservation of energy. Begin by stating E1=E2. In the first energy state, the ball is at the top of the ramp with no kinetic energy and its energy stored as only potential. In the second energy state (E2), the ball will have converted all of its energy from potential to kinetic. As a result, energy from the top was not lost but was only converted to kinetic as it reached the bottom. In this case, PE=KE, or mgh=1/2mv^2. Plugging in what we know, 1/2mv^2(KE)=39.2 Joules or 40 Joules.
