A cannon on a railroad car is facing in a direction parallel to the tracks (the figure below ). It fires a 99-kg shell at a speed of 105 m/s (relative to the ground) at an angle of 60 above the horizontal. If the cannon plus car have a mass of 4.6 104 kg, what is the recoil speed of the car if it was at rest before the cannon was fired?
1 answer
change athe speed of the shell to horizontal speed, then use the conservation of momentum principle.