A body of mass 3kgs moving at 4m/s collidea with a body of mass 5kgs moving at 2m/s in the same direction. what is tge common velocity of bodies if they stick together on collision?

Asmall electric heater, immersed in 80g of water in a calorimeter of 40j/k raises the temperature from 10.5 degree celsius to 25 degree celsius in 12 minutes. using the same apparatus with 50g of oil instead of water, it is found that the temperature of oil rises from 7 degree celsius to 27 degree celsius in 10 minutes. find specific heat capacity of the oil.