Question

A 100 kg cannon fires a 7.50 kg cannonball to the right with a velocity of 15 m/s. Find therecoil velocity of the cannon.

Answer 1

Given,

The mass of the cannon, M=100 kg

The mass of the cannonball, m=7.50 kg

The velocity of the cannonball, v=15 m/s

From the law of conservation of momentum, the total momentum of a system remains constant at all times. Thus in order to give momentum to the cannonball, the cannon should acquire momentum equal in magnitude in the opposite direction.

Thus,

`Mu=mv`

Where u is the recoil velocity of the cannon.

On substituting the known values,

`\begin{gathered} 100* u=7.50*15 \\ \Rightarrow u=(7.50*1.50)/(100) \\ =1.125\text{ m/s} \end{gathered}`

Thus the recoil velocity of the cannon is 1.125 m/s