Conservation of momentum

8.6 m/s

Explanation:

From the question,

applying law of conservation of momentum

Total momentum before collision = Total momentum after collsion

mu+m'u' = mv+m'v' Equation 1

make v' the susbject of the equation

v' = (mu+m'u'-mv)/m' Euqation 2

Where m = mass of the ball, m' = mass of the can, u = initial velocity of the ball, u' = initial velocity of the can, v = Final velocity of the ball, v' = final velocity of the can.

Given: m = 1.2 kg, m' = 0.7 kg, u = 14 m/s , u' = 0 m/s (at rest), v = 9 m/s.

Substitute these values into equation 2

v' = [(1.2×14)+(0.7×0)-(1.2×9)]/0.7

v' = (16.8-10.8)/0.7

v' = 6/0.7

v' = 8.6 m/s

d. air pressure decreases as altitude increases.