# Homework Help: Particle motion described by a time dependent function x(t)

1. May 27, 2006

### elizabethR

how would i do this...
A particle moving along the x-axis has its position described by the function x=( 2.00 t^{3}- 5.00 t+ 1.00 )\; {\rm m}, where t is in s. At t= 4.00 , what are the particle's position- i calculated that to be 109m , velocity, and acceleration?

i have tried for over an hour on this one problem. i am clueless. my physics book sucks!

2. May 28, 2006

### Pyrrhus

Show some work, so we can point out what's wrong.

Btw, for the position at t=4, you already have the x(t) (position function), for velocity and acceleration, look up the definitions.

$$v = \dot{x}$$

$$a = \dot{v} = \ddot{x}$$