Question

A 15-kg bicycle carrying a 50-kg boy is traveling at a speed of 5 m/s. What is the KE of the bicycle and the boy?

Answer 1

Together as one moving package, their mass is (15 + 50) = 65 kg.

       Kinetic energy = (1/2) (mass) (speed)²

                               = (1/2) (65 kg) (5 m/s)²

                               =  (32.5 kg) (25 m²/s²)

                               =     812.5  kg-m²/s²  =  812.5 joules .