Question

A railway truck of mass 20 tonnes, moving at 6.5 km/h is brought to rest by a buffer stop. The buffer exerts a force of 22.5 kN initially and this force increases uniformly by 60 kN for each 1 m compression of the buffer. Neglecting any loss of energy at impact, find the maximum compression of the buffer and the time required for the truck to be brought to rest.

Answer 1

$$K=W\\0.5mv^2=Fx+0.5kx^2\\0.5(20000)\frac{6.5^2}{3.6^2}=22500x+0.5(60000)x^2\\x=0.733\ m$$