Question

in a closed system consisting of a cannon and a cannonball, the kinetic energy of a cannon is 72,000 j. if the cannonball is 18 kg and has a velocity of 23 m/s when fired from the cannon, what is the total kinetic energy of the system? (1 point)

76,761 j

67,239 j

71,793 j

72,207 j

Explanation:

Step1: Calculate cannonball's KE

The formula for kinetic energy is $KE=\frac{1}{2}mv^{2}$. Given $m = 18$ kg and $v=23$ m/s, we have $KE_{cannonball}=\frac{1}{2}\times18\times23^{2}$.
$KE_{cannonball}=9\times529 = 4761$ J.

Step2: Calculate total KE

The total kinetic energy of the system $KE_{total}=KE_{cannon}+KE_{cannonball}$. Given $KE_{cannon}=72000$ J, then $KE_{total}=72000 + 4761=76761$ J.

Answer:

76,761 J