Question

If a stationary cart is struck head-on by a cart with twice mass of the stationary one and a velocity of 5 m/s, what will be the new velocity of the stationary cart if the collision is inelastic? Show all calculations leading to an answer.

Answer 1

@theEric

Answer 2

Alright! So, this is an inelastic collision. Do you know what that means, and what it means for the physics?

Answer 3

hold on im getting my notes out haha

Answer 4

Haha, good idea! :)

Answer 5

ok so i do know it i just cant find it in m brain or my notes hahah

Answer 6

@theEric

Answer 7

Sorry, OpenStudy quit on my computer for a moment.

Inelastic means that, while the total energy is conserved (as \(\sf always\)), the mechanical energy is not. This is often the case - some energy "transforms" into heat. With colliding cars, you'll see that it takes energy to make a dent, but the dent doesn't give that energy back. It's inelastic.

For the physics, it means we can't count on the conservation of mechanical energy. So, we shouldn't try to use potential or kinetic energy.

We will use the conservation of momentum, then.

Answer 8

ahhh ok haha

Answer 9

That is, the momentum before the collision must be equal to the momentum afterwards.

Momentum is a vector, and they add like vectors. So, momentum adds up, and we need to consider positive/negative direction if that is ever an issue.

Answer 10

So, let's address the givens, now that we explained some of the general information of the problem.

Answer 11

im lost but keep teaching hahah i wanna get this class over and done with haha

Answer 12

Gotcha.

So we have two cars. We want to know what's going on with them before the collision and after.

So, the mass is the same throughout. Using the given information, if the mass of the initially stationary cart is \(m\), then what is the mass of the initially moving car?

Answer 13

will it be |(m|) to

Answer 14

One more try!
"If a stationary cart is struck head-on by a cart with twice mass of the stationary one..."

Answer 15

so |(m|)^2

Answer 16

So, there's a stationary cart. There's also the other cart that hits the first. The moving cart has twice the mass of the stationary. So, if the stationary cart has mas \(m\), then the moving cart has mass \(2m\).

Answer 17

i was close just neede to rearrange haha