# Need help with Kinematics !

• Aug 29th 2005, 04:48 AM
rockwell
Need help with Kinematics !
Hi can everyone help me solve this exercise !

A particle moves in a straight line so that its position x m from a fixed point O on the line at any time t is give by X=t^3 -12t .

a. its velocity and acceleration at any time t
b. Its initial velocity and acceleration.

Thanks You
• Aug 29th 2005, 06:38 AM
hoeltgman
Position, velocity and acceleration stand in a direct relation.
If you have the function that describes the position, then the derivate of that function will give you the function of the velocity. The derivate of the velocity function will give you the acceleration.

So that you get here:

X= t^3 - 12t
V= 3t^2- 12
A= 6t

For finding the initial values, just insert t=0 if you suppose that the initial moment is when t=0.
• Aug 29th 2005, 07:53 PM
rockwell
That's great ...thanks you ...But what kind of this methods use to sole this equation ...can u tell me ...or give me the general formular for this...
• Aug 29th 2005, 11:02 PM
hoeltgman
Do you mean the formulas for the derivation of the function or the methods to find the zeros of the functions?
• Aug 30th 2005, 04:07 AM
rockwell
Yes , i mean the formulas for the derivation of the function ...thanks for you reply ...
• Aug 30th 2005, 05:02 AM
hoeltgman
Look at the following pdf file. It's pretty complete.