- #1
andrewn
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Homework Statement
A ball is traveling horizontally over a volleyball net when a player spikes it, driving it straight down to the ground. The ball's mass is .22kg, its speed before being hit is 6.4 m/s and its speed immediately after the spike is 21m/s. What is the magnitude of the impulse from the spike? I have two attempts at the solution but I was mainly wondering which attempt(s) is correct.
Homework Equations
impulse=change in momentum= (mass)(final velocity)-(mass)(initial velocity)
The Attempt at a Solution
J=.22(21)-.22(6.4)=3.212kg(m/s)
I don't know if that is correct because a way I was given to do this was using coordinates:
.22(0,21)-.22(6.4,0)=(0,4.62)-(1.408,0)=(-1.408,4.62)kg(m/s)