A child and a parent are running. The ratio of their masses is 1:2, and the ratio of their speeds is 3:1. What is the ratio of their kinetic energies?
A)2:9
B)3:2
C)9:2
D)9:4

Question

Quizplus · Accepted Answer

The kinetic energy (KE) is given by the formula KE = 1/2 * m * v^2, where m is mass and v is velocity. Given the ratios of their masses (m_child:m_parent = 1:2) and their speeds (v_child:v_parent = 3:1), we can calculate the ratio of their kinetic energies. For the child, KE_child = 1/2 * 1 * (3)^2 = 9/2, and for the parent, KE_parent = 1/2 * 2 * (1)^2 = 1. The ratio of their kinetic energies is therefore KE_child:KE_parent = (9/2):1 = 9:2.

A Child and a Parent Are Running