A2150 kg car, moving east at 10 m/s, collided and joins with a 3250 kg car. the cars move east together at 5.22 m/s. what is the 3250 kg car's initial velocity calculated to the nearest tenth?

The second car was moving at 2.1 m/s to the east

Explanation:

Conservation Of Linear Momentum

The total momentum of a system of bodies is constant if no external force is applied to it. The momentum of a body with mass m and velocity v is p=mv. When two objects collide and join together afterward, the total mass is the sum of the individual masses, and the final speed is common to both.

Let's say

are the masses of the objects 1 and 2, their speeds, and their linear momentums respectively before the collision, and

are the speeds of each object and their linear momentums after the collision.  

The principle of conservation of linear momentum states that

This means that

Since both cars remain together after the collision,

The relation becomes

Solving for

The given data is

Let's assume all the speeds are positive towards East

Replacing those values  

The second car was moving at 2.1 m/s (to the nearest tenth) to the east

is it really?

Explanation: