Help with Kinetic and Potential Energy

[tibessiba]

Homework Statement

A 51.0 skateboarder wants to just make it to the upper edge of a "quarter pipe," a track that is one-quarter of a circle with a radius of 3.30 . What speed does he need at the bottom?

Homework Equations

I have no idea where to start with this problem. Physics is sooo difficult for me!

The Attempt at a Solution

The furthest I got was to figure that length of the quarter pipe would be 5.184 m because one quarter of the circumference, which I calculated to be 20.735 m, would be 5.184m. I'm not sure if this was necessary or not.

 

[tibessiba]

P.S.
I am new to this site, and very greatful that such a site exists. Please let me know if I am not using the proper ettiquite.

Thanks

 

[plutoisacomet]

hi

You are doing great. Before you try to solve the problem. always write down your given values and the values that your looking for as well as the equations required to solve this group ( Ke and PE problems). I have a question for you. From the given information do you know what your final velocity could be? That may be one of your given variables.

 

[plutoisacomet]

Also, do you know if you are dealing with conservative or non-conservative forces etc.

 

[tibessiba]

I assume it to be conservative forces because that is what we have been focusing on in class.
The only given values for this problem are:
the mass of the skateboarder = 51.0 kg
the fact that the quarter pipe is one quarter of a circle with radius 3.30 m

I am not sure how I would go about calculating the velocity in this case. I have a distance, but no time reference.

Equations:

KE = 1/2 mv^2
U_g = mgy (gravitational energy)
K_f + U_g_f = K_i + U_g_i
E_mech = K + U (mechanical energy)