How Do You Calculate Acceleration and Ground Component on an Inclined Ramp?

[ladolce]

Homework Statement

A skateboarder, starting from rest, rolls down a 15.0 m ramp. When she arrives at the bottom of the ramp her speed is 7.95 m/s.

(a) Determine the magnitude of her acceleration, assumed to be constant.

(b) If the ramp is inclined at 23.0° with respect to the ground, what is the component of her acceleration that is parallel to the ground?

Homework Equations

v squared=v initial squared +2ax
kinematics equations..

The Attempt at a Solution

I tried so many times to get the answer! I tried making a right triangle with 23 degree angle and cos 23=x/2.1, it didnt work out...i'm so confused, please help!

 

[Doc Al]

Seems OK to me. How do you know it's wrong? Did you use enough significant figures?

 

[ladolce]

I don't know, that's probably it though! I'm using webassign and it tells u if its wrong or not

 

[Doc Al]

What did you enter exactly?

 

[ladolce]

Yeah, that's it. Haha, dumb Webassign! That was the first answer I put in too.
Thanks so much =)

 

[i.mehrzad]

Beginning the way DocAl begins it is fairly a easy question.
I can help you in the first part,
use the equation v^2=u^2+2as
all the data is given in the quation and after getting this part i would prefer that you think about it.