One object of mass 20 kg is moving with speed 10 ms-1 in west direction and another object of mass 10 kg is moving with 15 ms-1 in north direction. Both collide and stick together. Choose the correct alternative. [JIPMER 2019]

When object of mass 20 kg moving with speed 10 ms-1 in west direction collides with object of mass 10 kg and both of them stick together, hence it is perfectly inelastic collision. In inelastic collision, only momentum is conserved.