Speed/Collision question?

Question

A small, 300g cart is moving at 1.80 m/s on an air track when it collides with a larger, 4.00 kg cart at rest. After the collision, the small cart recoils at 0.880 m/s .

What is the speed of the large cart after the collision?

Answer 1

Momentum Conservation

Momemtum before collision = Momementum after collision

Momentum =  mass*velocity

so the equation looks like this

m1*v1 +m2*v2 = m1*v1' + m2* v2'

First let's get our units consistent and put everthing in kg

m1 = 300g = 0.3kg

m1, v1 mass and velocity of small cart before collision

v1' velocity of small cart after collision

also notice that the velocitcy of the large cart is zero before the collision, so v2=0

Then we just plug in all the values and solve for v2'

(0.3kg)*1.8m/s + 4kg*0m/s = 0.88m/s*(0.3kg) + 4*v2'

v2'=0.069 m/s

The link below has a lot of good examples of this idea.