Final answer:
The gravitational potential energy (G.P.E.) formula is used to find the velocity of a mass moving due to gravity. The correct velocity formula is v = √(2gh), which means answer choice A is correct for a mass of 20 kg at a height of 15m with an energy of 4,900 joules.
Step-by-step explanation:
The question involves calculating the velocity of a mass that is moving due to gravitational forces, which is a Physics problem typically encountered at the High School level. According to the provided information, the gravitational potential energy (G.P.E.) of the mass is given by the formula G.P.E. = mgh, where m is mass, g is the acceleration due to gravity, and h is the height.
In this case, the energy associated with the mass due to its height is given as 4,900 joules, and the value of g is 9.8 m/s². To find the velocity (v) of the mass, we can use the formula v = √(2gh), by rearranging the kinetic energy formula.
Therefore, the velocity of a 20 kg mass at a height of 15m with energy of 4,900 joules is given by:
v = √(2 × 9.8 m/s² × 15m)
Calculating this yields the velocity of the mass as it moves, which corresponds to answer choice A. v = √(2gh).