A railway carriage of mass 9000 kg moving with a speed of `36kmh^(-1)` collides with a stationary carriage of same mass. After the collision, the carriages get coupled and move together. What is their common speed after collision? What type of collision is this?

Explanation

`m_(1)=9000kgkg,u_(1)=(36km)/h=(10 m)/s`
`m_(2)=9000kg, u_(2)=0,v=v_(1)=v_(2)= ?`
BY conservation of momentum :
`m_(1)u__(1)+m_(2)u_(2)=(m_(1)+m_(2))v`
`therefore v=(5m/s)`
`"total K.E. before collision"=1/2m_(1)u_(2)^(2)+1/2m_(2)u_(2)^(2)=45000J`
`"Total K.E. after collision =1/2(m_(1)+m_(2))v_(2)=225000J`
`"As total K.E. after collision" lt "total K.E.before collision"`
`therefore "collision is inelastic".`