- #1

circuscircus

- 15

- 0

## Homework Statement

A particle moves in the xy plane with constant acceleration. The particle is located at [tex]\vec{r} = 2\hat{i} + 4\hat{j}[/tex] m at t=0s. At t=3s it is at [tex]\vec{r} = 8\hat{i} - 2\hat{j}[/tex] m and has a velocity [tex]\vec{r} = 5\hat{i} - 5\hat{j}[/tex] m/s

What is the particle's acceleration vector a?

## Homework Equations

## The Attempt at a Solution

Here's what I did

[tex]\vec{a} = (\hat{r_{1}} - \hat{r_{2}}) / \Delta t - \vec{r} = 5\hat{i} - 5\hat{j}[/tex]

The answer is just that without the [tex]\vec{r} = 5\hat{i} - 5\hat{j}[/tex]

Could someone tell me why?