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Homework Statement
A satellite with a mass of 252 kg approaches a large planet at a speed vi,1 = 12.3 km/s. The planet is moving at a speed vi,2 = 11.3 km/s in the opposite direction. The satellite partially orbits the planet and then moves away from the planet in a direction opposite to its original direction (see the figure). If this interaction is assumed to approximate an elastic collision in one dimension, what is the speed of the satellite after the collision?The answer is 34.9 km/s.
Homework Equations
The Attempt at a Solution
I think the key words here are "elastic collision." Kinetic energy will therefore be conserved, as should momentum.
I don't understand how to approach the problem since I have no information about the final momentums/velocities of either object. I can't imagine the satellite changing the velocity of the planet to any consequential amount, but using the same velocity (11.3 km/s) for its initial and final states will only result in the satellite having the same initial and final velocities (in opposite directions).
The satellite changes direction so I tried
M1V1+M2V2=M1fV1f+M2V2
252(12.3)+M(11.3)=252(-v)+M(11.3)
which again suggests that vf=-12.3
any assistance much appreciated.