A flat-bed railway wagon of mass is initially at rest on a smooth horizontal track
PHYSICS · Multi-part · CBSE · Physics · Work and Energy · Work and Energy
Problem
A flat-bed railway wagon of mass 8000kg is initially at rest on a smooth horizontal track. Three identical crates, each of mass 250kg, are gently lowered onto the wagon one after another so that they land without bouncing and move together with the wagon. Immediately after the third crate has been loaded, the wagon is observed to be moving at 2.5m s−1.
(a) Determine the total mass of the wagon–crate system after all three crates have been loaded.
(b) Calculate the kinetic energy of the loaded wagon–crate system at 2.5m s−1.
(c) The wagon is later pushed by a locomotive and its speed increases uniformly to 7.5m s−1. Compute the additional kinetic energy gained by the system during this acceleration.