Introductory Conservation of Momentum Explosion Problem Demonstration

Now that we have learned about conservation of momentum, let’s apply what we have learned to an “explosion”. Okay, it’s really just the nerd-a-pult launching a ball while on momentum carts.
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This is an AP Physics 1 Topic.

0:00 Intro
0:38 The demonstration
1:16 The known values
2:07 Solving the problem using conservation of momentum
4:00 Measuring the final velocity of the nerd-a-pult
4:39 Determining relative error
5:09 What happens with a less massive projectile?

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[micahcampbell]

For the .004kg wooden ball I think it's cuz the total momentum was much smaller (since the mass decreased) and couldn't overcome the small amount of friction there was between the tracks and the carts.

[eaglekraft]

If the displacement of the wood ball is the same as the displacement of the brass ball. Then the Nerd-a-Pult's Velocity would be .009 m/s which is around 17 times lower than the velocity of the Nerd-a-Pult if the brass ball was used. I guessing the velocity of the Nerd-a-Pult from the wood ball (.009) is not enough to get it moving because it would have to overcome the static friction. Is this correct?

[neurodivergentsophie]

The wooden ball has way less mass than the brass ball(the brass ball has 16.5x more mass than the wooden ball) so the change in momentum of the Nerd-A-Pult was not enough to overcome the friction between it and the tracks.

[lakshman.n]

Mr.P pls say should I always consider the horizontal velocity ? . Why not inclined velocity in projectile motion ?

[AyalaMrC]

Technically, you should not have been able to calculate your relative error, since any disagreement in values is smaller than the resolution allowed by your significant digits. With both values rounded to a proper 15 m/s, your relative error should essentially be zero.
On a side note, I must admit that my 80s trivia was not up to the task of identifying your character, but two of my students figured it out.

[danielir]

The static friction force between the cart and the track is large enough to not be overcome by the change in momentum caused by the wooden ball?

[pat]

The nerd-a-pult does not move because it has 447.75 times the mass of the wooden ball. Thus, as the total momentum must be conserved, but because the wooden ball has very little momentum (due to its mass), the nerd-a-pult has the same momentum, but negative (because the initial momentum is zero). The momentum of the nerd-a-pult after the explosion is not exactly zero, because the ball has momentum, very little due to its mass, but it has. Therefore, the nerd-a-pult must move, though a really small amount of distance.

[neurodivergentsophie]

LMAO, Nerd-A-Pult, is a hilarious pun XD!

[runjinyean]

Why bo doesn't use Newton's third Law to explain that. 0:53

[Uncertaintycat]

WHO EES EET, MAN?! I have to know!!! And also, apparently, I should lay off the coffee.

[atharvacjoshi]

since the mass of the wooden ball is way too less than that of the brass... the momentum offered by the wooden ball is very less compared to brass ball... therefore the "nerd-a-pult" had pretty much no velocity