Three objects move on a straight road: a bicycle of mass 20 kg
PHYSICS · Multi-part · AP · Physics 1: Algebra-based · Work Energy and Power · Work Energy and Power
Problem
Three objects move on a straight road: a bicycle of mass 20 kg, a scooter of mass 100 kg, and a small truck of mass 1 000 kg. At a particular instant each of them is travelling at 5 m/s.
(i) Define kinetic energy and write its mathematical expression.
(ii) Calculate the kinetic energy of each object and arrange them in ascending order of kinetic energy.
(iii) If only the truck reduces its speed to 2.5 m/s while the other two keep moving at 5 m/s, by what factor does the truck’s kinetic energy change?
(iv) Using your answers to parts (ii) and (iii), explain how kinetic energy depends separately on (a) mass and (b) speed of a body.