The kinetic energy before it hits Max’s shoulder is
1/2 mv^2
Where m is mass
v is velocity
So, the kinetic energy of the dart before it’s hits the poor kid is
Ek = 1/2 • 0.1 • 30^2
Ek = 45J
Then, we see that the dart comes to a stop inside Max’s shoulder. This means there’s no movement, and therefore no kinetic energy.
Change is always (final - initial)
So, (0-45) = -45 Joules.
Mark brainliest!