Question

Please help! Giving 20 points!!

If two train cars, one of mass 1000 kg and the other of 1750 kg, are next to each other and connected by a compressed spring, and the spring releases so that the heavier car moves off at 4 m/s, what is the velocity of the other car?

Answer 1

Step-by-step explanation:

Remark

This is a momentum question. Both cars are sitting still (v1 and v2 are both 0) to start with). When the spring is sprung), they both move but in opposite directions.

Let us say that v4 is minus.

Equation

0 = m3*v3 - m4* v4

Givens

m3 = 1750 kg

m4 = 1000 kg

v3 = 4 m/s

Solution

m3*4m/s - m4*x = 0

1750 * 4 - 1000*x = 0

1750 * 4 = 1000x

7000 = 1000 x

7000/1000 = x

x = 7 m/s