Which one is it b or D? ASAP plz and thank you?

What object a collides with object b and bounces back its final momentum is?

The rocket is fired vertically and tracked by the radar station shown. when θ reaches 66°, other corresponding measurements give the values r = 32700 ft, r¨ = 85 ft/sec2, and θ˙ = 0.019 rad/sec. calculate the magnitudes of the velocity and acceleration of the rocket at this position.

What is special about a dc circuit ?