An 800 kg passenger train car moves to the east at a constant horizontal speed of 15…
PHYSICS · Multi-part · CBSE · Physics · Work, Energy and Power · Work, Energy and Power
Problem
An 800 kg passenger train car moves to the east at a constant horizontal speed of 15 m/s relative to the ground. A suitcase with mass 20 kg is initially at rest on the floor of the car (so its speed relative to the train car is zero).
Two observers make measurements:
• Observer G stands on the ground beside the tracks.
• Observer T rides inside the train car.
Answer the following questions from the perspectives of the two observers.
(a) Determine the numerical value of the suitcase’s translational kinetic energy that would be calculated by Observer G and by Observer T, respectively.
(b) Using clear reasoning, explain why the two observers obtain different numerical values even though they are analyzing the same physical object at the same instant.
(c) The observers next discuss whether the suitcase’s translational kinetic energy has a direction associated with it. State their conclusion and provide a brief justification founded on the definition of kinetic energy.