No. As the potential energy can have a negative value, the total energy of the system may sum up to zero.For example:Two masses A and B having masses 2 kg and 4 kg respectively move with a velocity of 4 ms−1 in opposite directions.Kinetic energy of system (A and B)=21​×2×42+21​×4×42 = 48 JIf the gravitational potential energy of the system is −48 J,the total energy of the system will be zero. However, the linear momentum will be non-zero.