A 455 kg cannon fires a 21 kg cannonball at 26 m/s. If the cannon is on wheels, at what velocity does it move backward?

A cannon ball of mass 4.0 kg is fired from a stationary 96 kg cannon at 120 m/s. Calculate the velocity of the cannon immediately after firing.

total momentum of cannon and cannon ball before = 0 kg m/s - because neither object is moving

total momentum of cannon and cannon ball after collision = 0 kg m/s - because momentum is conserved

Momentum of cannon ball after firing = 4.0 × 120 = 480 kg m/s.

Momentum of cannon after firing = -480 kg m/s (because it recoils in the opposite direction and 480 - 480 = 0 kg m/s, the total momentum after collision).

Rearrange p = m v to find v:

v = p/m

v = 480 divided by 96

v = 5.0 m/s

Note that the forward velocity of the cannon ball was given a positive value. The negative value for the cannon's velocity shows that it moved in the opposite direction.

the answer is c. the lower legs are levers, and the knees are fulcrums. the ankles hold the loads.