Question

Match the letters with the correct description below.

A. point A
B. point B
C. point C


ABCpoint with maximum potential energy

ABCpoint with minimum potential energy

ABCpoint with maximum kinetic energy

ABCpoint with minimum kinetic energy

Answer 1

Can anyone help?

Answer 2

Let's start with KE. When do you think KE is at max?

Answer 3

at b right?

Answer 4

Think of it this way....if you start rolling down a steep hill, when will you be going the fastest?

Answer 5

At point C

Answer 6

Yes. Your KE will be the highest at point C because:\[KE=\frac{1}{2}mv^2\]Knowing that, at what point do you think you'd be moving the slowest?

Answer 7

(think of being on a roller coaster)

Answer 8

At point a

Answer 9

And I can't stand roller coasters aha

Answer 10

Yes, at point A you would be moving slower than you would at point C. This is because you have accelerated down the hill increasing your velocity...which as you can see in the first formula, increases your KE. Now let's talk about PE. PE is potential energy due to your position.
\[PE=mgh\]At point A you're at max PE because your height is at a maximum point. Conversely, at point C, PE is at a minimum.

Answer 11

Just remember, in this situation you're starting at a max PE because of the height (h). As you go down the hill, the PE will decrease as KE increases (due to your increase in velocity).

Answer 12

So would point b have the least potential energy?

Answer 13

oops...typo there.

Point C would have the least PE...but the most KE. Point A would have the most PE but the least KE. The values for point B don't even matter in this problem.

Answer 14

If it's not clear, point B shows you that KE is 600J and PE is 400J. As the cart rolls further down the hill, KE is still increasing (since you're still speeding up) and PE is still decreasing (since your height is decreasing).

So as I said, point B isn't really that important...it's just there to show you the values at the one point.

Does all of that make sense?

Answer 15

Yes it does so my choices are A,B,B,A

Answer 16

A C C A :)

Answer 17

I meant C,C

Answer 18

And thanks for the help:)

Answer 19

No problem. In the future make sure you just memorize these formulas:\[PE=mgh\]\[KE=\frac{1}{2}mv^2\] Then think about how the height and velocity would be at each point and it should help.

Answer 20

Will do

Answer 21

Good luck!

Answer 22

Thanks