Conservation of Momentum

azizlwl

Two 140-kg satellites collide at an altitude where g=8.7m/s²
and the collision imparts an impulse of 1.8x10⁵N.s to each. If
the collision lasts 120 ms, compare the collisional impulse to that
imparted by gravity. Your result should show why you can neglect
the external force of gravity.

Ans: The impulse imparted by gravity is
0.08% of the collision impulse.

Not sure how the gravity effect the collision since is tangential to the orbit. My line of thinking is that the forces due to gravity is cancelled out.

Thank you.

Doc Al

No information was given as to the direction of the impulse due to the collision. Regardless, you can calculate the impulse due to gravity and compare its effect to that of the collision forces.