An ice hockey puck slides along the ice at 12 m/s. A hockey stick delivers an impulse of 4.0 kg * m/s causing the puck to move off in the opposite direction with the same speed.
What is the mass of the puck?
Known variables:
initial velocity (v1) : 12 m/s
final velocity (v2) : -12 m/s (opposite direction)
impulse: 4 kg * m/s
Impulse is the change in momentum
Ft = mv1-mv2
Ft = m(v1-v2)
4 = m [12-(-12)]
-24m = 4
Solve for m:
m = 1/6 or
m = .17 kg
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