The total mechanical energy is the sum of the kinetic energy and the potential energy. It is easier to solve for the potential energy in this case because we are given with the position of the apple.
PE = mgh
Substituting the mass, acceleration due to gravity and the height,
PE = (0.1 kg)(9.8 m/s²)(1 m) = 0.98 J
Then, we solve for the velocity at that point. The distance it had traveled is 0.5 meters.
d = v²/g ; 0.5 = v²/9.8 m/s²
v = 2.213 m/s
Then, solving for KE
KE = 0.5mv²
Substituting,
KE = 0.5(0.1 kg)(2.213 m/s)² = 0.245 J
Adding the two mechanical forces will give us an answer of 1.225 J. Thus, the answer is the first choice.
