# Collision in 2 dimensions (Momentum)

## Homework Statement

Two spacecrafts have linked in space and are coasting with their engines off, heading directly towards Mars. The spacecrafts are thrust apart by large springs. Spacecraft 1 with mass of 1.9 x 10^4 kg, then has a velocity of 3.5 x 10^3 km/h at 5.1 degrees to its original direction. Spacecraft 2 with mass 1.7 x 10^4 kg, has then a velocity of 3.4 x 10^3 km/h at 5.9 degrees to its original direction. Determine the original speed of the two craft when they were linked together.

2. The attempt at a solution
Please see attached my attempt to solve this question. Am I on the right path? Do I have to calculate for Y axis too? Many thanks

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Update:

So Basically, I know now that the force of the spring is in fact internal. But, if there is no velocity on the y axis why would I have to calculate it? And I on the right path performing calculations for the x axis only?

Cheers

You are indeed. The work done by the spring only acts in a Y direction so because of that, there is no change in speed in the x direction.

awesomeness.... thank you

From looking at your work, you forgot to convert the speeds from Km/h into m/s before plugging the numbers into the equation.