7. Jake is bowling with a 8 kg bowling ball. He rolls the ball at 7 m/s, and it hits one stationary pin with a mass of 2 kg. The pin goes flying forward at 12 m/s. How fast is the bowling ball now traveling?

This is a conservation of momentum problem. Initial momentum must equal final momentum.

Momentum = mass * velecoity

I will denote Ball as b and pin as p

Initial momentum = V (initial b) * Mass (b) + V (initial p) * mass (p)

since the pin is stationary to begin that means velocity is 0 and we can plug in for the rest

Initial momentum = 7m/s*8kg=56 mkg/s

Now for final momentum=V (final b) * mass (b) + V (final p) * mass (p) plugin

final momentum=V (final b) * 8kg+12m/s*2kg

we can set final momentum = inital momentum and solve for V (final b)

56mkg/s = V (final b) * 8kg + 24mkg/s

32mkg/s=V (final b) * 8kg

4m/s=V (final b)

so 4 meters/second is the answer