A train moves east at relative to the ground

PHYSICS · Single correct · AP · Physics 1: Algebra-based · Kinematics · Kinematics

Problem

A train moves east at

15\,\text{m/s}

relative to the ground. From inside the train, a passenger throws two identical balls: ball P is thrown east at

10\,\text{m/s}

relative to the train, and ball Q is thrown west at

10\,\text{m/s}

relative to the train. Ignoring air resistance, what is the ratio

K_{P}/K_{Q}

of their translational kinetic energies as measured by a stationary observer on the ground? (a)

6.25

(b)

1

(c)

25

(d)

5