If you throw a ball horizontally while standing on a skateboard, you roll backward with a momentum that matches that of the ball. Will you roll backward if you hold onto the ball while going through the motions of throwing it? Explain in terms of momentum conservation.
According to the law of conservation of momentum, the total momentum of a system remains constant if no external forces act on it. In this situation, we have a system consisting of you, the skateboard, and the ball.
When you throw a ball horizontally while standing on a skateboard, you exert a force on the ball, causing it to move forward with a specific momentum. As a reaction to this force, the ball exerts an equal and opposite force on you, creating an equal but opposite momentum. Due to the low mass of the ball compared to your mass, the change in momentum you experience is negligible.
Now, let's consider what happens if you hold onto the ball while going through the throwing motion. When you release the ball, you transfer its momentum to the ball and it moves forward. However, since you are holding onto the ball, your momentum is also transferred to it. As a result, you would still roll backward with the momentum that matches that of the ball.
In other words, regardless of whether you release the ball or hold onto it, the total momentum of the system (you, the ball, and the skateboard) remains the same as long as no external forces (such as friction or air resistance) come into play. Therefore, you would still roll backward with the same momentum as the ball if you hold onto it while going through the throwing motion.