Roller coaster problem with height and forces

[alexcc17]

Homework Statement

http://img684.imageshack.us/img684/4316/capturerey.jpg

Homework Equations

The Attempt at a Solution

I am completely stuck on this. I thought I would use W=F=ma, but that wouldn't take the height into account. Any help would be greatly appreciated

 

[Nessdude14]

To find the velocity at the second peak, you can use conservation of energy:

$\displaystyle ΔU_g = mgΔh$
U_g is potential gravitational energy

$\displaystyle K_E = -ΔU_g = \frac{1}{2} mv^2$And to find the apparent weight of the passenger, you can use the circular motion equation:

$\displaystyle F_{net} = \frac{mv^2}{r}$

Hope that helps.

 

[PhanthomJay]

Yikes the heights are in meters but the weight is given in pounds. No wonder why they stopped teaching mixed units in the States. Watch your unit conversions, please.

 

[alexcc17]

Thank you!