# Parametric equations -> acceleration

1. Feb 5, 2013

### burton95

parametric equations --> acceleration

1. The problem statement, all variables and given/known data

An object is moving at constant acceleration in the x-y plane. Its position and velocity at two different times are given by the following equations:
What is the magnitude of the object’s acceleration (in m/s2) as it moves from the first position to the second position? Hint: solve for the acceleration along each axis separately.

2. Relevant equations
r1= (2m)i + (4m)j
r2= (10m)i + (14m)j

v1= (1m/s)i + (8m/s)j
v2= (7m/s)i + (2m/s)j

3. The attempt at a solution

I decided to calc magnitude of the velocity

$\left\|$v1$\right\|$ = (82+12)1/2 = 8.06

mag v2 = (72 + 22)1/2 = 7.2801

(Vf)2=(Vi)2 + 2asΔs

for y
(7.2801)2=(8.06)2+2as(10)
as = -.7457725

for x
(7.2801)2=(8.06)2+2as(8)
as = -.59818

√((-.598182)+(-.74577252) = .95755

Last edited: Feb 5, 2013
2. Feb 5, 2013

### rude man

Re: parametric equations --> acceleration

I would follow your instructor's hint and work with one coordinate at a time. Your eq's. don't make sense to me.

BTW I think you have to assume constant acceleration in this problem.

You might try the following:

1. write eq. for vx(t).
2. write eq. for x(t).

Eq's. 1 and 2 give you ax and T, the time of transit from r1 to r2.
3. do same for y.