
Two balls made of the same material collide perfectly inelastically as shown. The energy lost in the collision is completely utilized in raising the temperature of each ball. Find the rise in temperature of the balls. (Specific heat $=31$ cal/kg-$^\circ$C): 
Two rods of equal length \(60\,\text{cm}\) each are joined together end to end. The coefficients of linear expansion of the rods are \(24\times10^{-6}\^{\circ}\text{C}^{-1}\) and \(1.2\times10^{-5}\^{\circ}\text{C}^{-1}\). Their initial temperature is \(30^{\circ}\text{C}\), which is increased to \(100^{\circ}\text{C}\). Find the final length of the combination (in cm).
