A 1 kg mass is sliding along a frictionless surface at plus 6 ms and collides with another object mass equals 3 kg at rest The collision is perfectly inelastic What is the velocity of the 1kg obj?

In a perfectly inelastic collision, the two objects stick together and the momentum is conserved. Once the objects stick together, they both have the same velocity.

p = mv

where p is the momentum

conservation of momentum for perfectly inelastic collision:

m1v1i + m2v2i = (m1 + m2)vf

(1kg)(6m/s) + (3kg)(0m/s) = (1 kg + 3kg)vf

6 kg·m/s = (4kg) vf

vf = v1f = v2f = 1.5 m/s