Sam is hit by a baseball moving at 10 m/s, but claims it didn't hurt at all! His "friend" Alex then hits another ball at him, this time at 20 m/s, and it really hurt Sam! What accounts for this difference in impact felt?
A)Double the speed results in 4 times the kinetic energy.
B)Double the speed results in more force applied in a smaller area.
C)The ball was moving faster, and thus compressed air in front of it into a small sonic blast.
D)The second ball was a curveball.
E)Sam is lying, and the second ball didn't hurt either.

Question

Quizplus · Accepted Answer

A ball moving at twice the speed has 4 times the kinetic energy. Kinetic energy is calculated by E = ½*mv2, so velocity is the greatest factor. Thus, although the ball was moving twice as fast, it held 4 times the energy as the first ball, resulting in a much bigger impact.

Sam Is Hit by a Baseball Moving at 10 M/s