A massive truck of 1200N moving with a velocity of 2m/s hits a stationary mass of 30N. if the both bodies move together after the collision, determine their common velocity.

The common speed is 1.95 m/s

Explanation:

Law Of Conservation Of Linear Momentum

It states that the total momentum of a system of bodies is conserved unless an external force is applied to it. The formula for the momentum of a body with mass m and velocity v is  

P=mv.  

If we have a system of bodies, then the total momentum is the sum of all of them:

If a collision occurs, the velocities change to v' and the final momentum is:

In a system of two masses, the law of conservation of linear momentum

is written as:

If both masses stick together after the collision at a common speed v', then:

The common velocity after this situation is:

The truck of m1=1200 N (weight) travels at v1=2 m/s and hits a stationary mass (v2=0) of m2=30 N (weight). After the bodies collide, they keep moving together. Before we can calculate the common speed, we need to calculate the masses of the bodies, since they are given as weights.

Now calculate the common speed:

The common speed is 1.95 m/s

i don't know that i agree with that but what's the question ?