- #1

ldesai149

- 8

- 0

## Homework Statement

The velocity of an object moving along the x-axis is given by V

_{x}= (2.0t-t

^{2})m/s. Initially (at t=0), the object was at the origin.

a) Determine the object's acceleration at t=3.0s.

b) Find the object's position at t=3.0s

c) Calculate the object's maximum positive displacement from the origin.

## Homework Equations

a = dv/dt

x

_{f}= x

_{i}+ v

_{xi}t + (1/2)a

_{x}t

^{2}

v

_{xf}

^{2}= v

_{xi}

^{2}+ 2a

_{x}

## The Attempt at a Solution

[/B]

a) To get an equation for acceleration,

a

_{x}= dv/dt = d/dt (2.0-2t)

= 2.0 - 2(3.0s)

= -4.0 m/s

^{2}

b) x

_{f }= x

_{i }+ v

_{xi}t + 1/2a

_{x}t

^{2}

= (0 m) + (0 m/s)(3.0 s) + 1/2 (-4.0 m/s2)(3.0s)

^{2}

= -18.0 m

c) delta x = [v

_{xf}

^{2}- v

_{xi}

^{2}] / [2a

_{x}]

= [2.0 (3.0s) - (3.0s)

^{2}]

^{2}- [0 m/s] / [2 (-4.0 m/s

^{2})]

= -1.1 m

First of all, I'm not sure if I've done the derivation for the accleration equation correctly. Also, question c) asks for maximum POSITIVE displacement but I keep getting a negative value. I'm not sure where I'm going wrong!