A piece of putty and a tennis ball with the same mass are thrown against a wall with the same velocity. Which object experience a greater impulse from the wall or are the impulses equal? Explain.
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Okay, so I do what a tennis ball hits the wall. Let's say they're going the same speed in a piece of putty. It's all they have the same mass, Same speed. Um, which one, uh, experience is a greater impulse from the wall. The answer is it's gonna be the ball, but let me show you why. Okay, so let's imagine that we've got struck before and after dictionary. So here's the putty appear. This is putty, right? And the party use and use our wall. Right? So the party is moving in the first frame in the second frame. Putty has stuck to the wall because that's what he does. Just like Okay, so this thing is supposed to be the wall there. Okay, let's imagine that this thing's going. It's got one kilogram mass, right? And it's going whips. Let's say it's going five meters per second, right? Okay, So if we look at this impulse here, right the impulses, Well, it's forced times time, but it's also mass change in velocity, right? Okay. By the way, tennis ball isn't Kilogram, but we're gonna make our tennis ball be a kilogram.
All right? So if we look at this. We've got ah, one kilogram right and then our change of velocity is we were moving to the right of five meters per second. We stop so it's negative five right, so that's our That's our impulses. Negative five kilograms meters per second order. Newton seconds would be the same right now. Imagine we've got a tennis ball and we This is like the world's biggest tennis ball, right? And it's Ah, it's a one kilogram two this fall, right and it's going five meters per second. Big Turner's ball, the port important point years that the tennis ball is moving this way right and then afterwards it's gonna bounce off. Now it's not gonna go is fast. Maybe it's gonna be going negative for meters per second, right? Right. Even know, right? I'm just making up numbers here, but it's gonna be going some velocity, right? And there in lies the rub, because this change in velocity is from five meters per second to negative four, right? So that change of velocity is bigger. If you bounce off another way to say it is, it's and it's one thing to just exert a force that stops the ball. But if you not only stop the ball that send it back the other way, it's gonna be a bigger impulse. Bigger force, bigger time. Right? So in this case, it would actually be This would be this change of velocity is nine. Right? So people in kilogram times nine meters for saying that's just an example right to this rejection of the nine kilograms meters per second. If it had any velocity all coming off the wall, though I think we can all over you would be bigger than this. Okay, that's the important thing.