A cannon of mass 100 kg launches a cannonball of mass 10 kg at a velocity of 100 ms.At what time does the cannon recoil?

To find the time it takes for the cannon to recoil, we can use the law of conservation of momentum. Initially, the total momentum is 0 since the cannon is at rest. After firing, the total momentum is 10 kg * 100 m/s = 1000 kgm/s in the forward direction. The cannon will recoil in the opposite direction with the same momentum, so the recoil velocity will be -1000 kgm/s / 100 kg = -10 m/s. Therefore, it would take 1 second for the cannon to recoil.