A 0.168kg hockey puck slides at 11.4m/s. what is the work needed to stop the puck?

The work is equal to the change of kinetic energy

W=ΔK=K2-K1= 0-(mv^2)/2
W=0.168•(11.4)^2/2=10.9 J.

To calculate the work needed to stop the puck, you need to determine the initial kinetic energy of the puck and then subtract the final kinetic energy from it.

The formula for kinetic energy is:

Kinetic Energy (KE) = 1/2 * mass * velocity^2

First, calculate the initial kinetic energy using the given mass (0.168kg) and velocity (11.4m/s):

KE_initial = 1/2 * 0.168kg * (11.4m/s)^2

Simplifying:

KE_initial = 0.084kg * (11.4m/s)^2

KE_initial = 0.084kg * 129.96m^2/s^2

KE_initial ≈ 10.9176 Joules (J)

Since we want to stop the puck, the final velocity will be zero (0m/s). Therefore, the final kinetic energy (KE_final) will be zero.

Now, calculate the work needed by subtracting the final kinetic energy from the initial kinetic energy:

Work (W) = KE_initial - KE_final

W = 10.9176 J - 0 J

W ≈ 10.9176 J

Therefore, the work needed to stop the puck is approximately 10.9176 Joules.