Part a part complete imagine that you replace the block in the video with a happy or sad ball identical to the one used as a pendulum, so that the sad ball strikes a sad ball and the happy ball strikes a happy ball. the target balls are free to move, and all the balls have the same mass. in the collision between the sad balls, how much of the balls' kinetic energy is dissipated? view available hint(s) imagine that you replace the block in the video with a happy or sad ball identical to the one used as a pendulum, so that the sad ball strikes a sad ball and the happy ball strikes a happy ball. the target balls are free to move, and all the balls have the same mass. in the collision between the sad balls, how much of the balls' kinetic energy is dissipated? none of it all of it half of it previous answers correct the collision between the sad balls is completely inelastic, and due to the conservation of momentum, the velocity of the balls after the collision will be half the velocity of the incoming ball before the collision. the expression for kinetic energy is 12mv2, and while there is double the mass moving after the collision as before, the decrease in velocity by a factor of two results in the overall kinetic energy being half its initial value. part b now, consider the collision between two happy balls described in part a. how much of the balls' kinetic energy is dissipated?