Answer:
20.94 m/s
Explanation:
Recall that average velocity is defined as:
V = distance / time
Then, for our case:
V = 754 m / 36 sec = 20.94 m/s
I DONT know FiGURE it out YOURSELF
Answer:
The change in momentum is 
Explanation:
From the question we are told that
The time taken for the stone to stop is 
The net force on the rock is 
The impulse of the rock can be mathematically represented as

Substituting values


Now impulse is defined as the rate at which momentum change
Hence the change in momentum
of the rock is equal to the impulse of the rock
So

The force applied to the cannonball and cannon is equal. The explosion inside the cannon will generate a pressure which will turn into a force on both cannonball and cannon. The cannon being heavier and fixed to the ground will move a bit, but the cannonball will be thrown away, fired.