Radius of curvature for pin P moving in parabolic slot at t=6s

[student1]

Homework Statement

A guide with a vertical slot is given a horizontal motion of x=200cos(0.3t), where x is in mm, t is in seconds and (0.3t) in radians. The guide controls the motion of pin P, which is also constrained to move along a fixed parabolic slot as shown below. The parabolic slot has a shape given by the equation y=x(squared)/200, where y is in mm.

For the instant where t=6.0seconds,

(a) Determine the position, velocity and acceleration of P in X-Y components.

(b) Determine the rate at which the speed of P is changing.

(c) Determine the instantaneous radius of curvature of the path.

Im just stuck on part c

Homework Equations

a=v.t+ v^2/p

The Attempt at a Solution

Part a = done

Part b=done

Part c have no clue where to start

 

[eok20]

Well, the radius of curvature is 1/K, where K is the curvature. Do you know the definition of K? See http://en.wikipedia.org/wiki/Curvature

 

[student1]

could point me in the right direction using n-t coordinates

cheers