# Finding the magnitude of acceleration in 2D motion

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1. Oct 23, 2016

### Dano1337

1. The problem statement, all variables and given/known data
A car moving due south at 20.0 m/s enters a highway cloverleaf. The car will exit the cloverleaf to merge with westbound traffic traveling at 29.0 m/s.

The time between entering the cloverleaf and exiting to merge with westbound traffic is 20.7 s. What is the magnitude of the average acceleration of the car?

For the units, use a ^ to indicate an exponent.

2. Relevant equations
magnitude eq = v = sqrt (x^2)+(y^2)
average a = change in velocity / change in time

3. The attempt at a solution
1. sqrt ((20^2)+ ((29^2)) = 35.2 m/s
2. 35.2 / 20.7 = 1.7 s
any help or advice on where I'm going wrong would be very much appreciated.

2. Oct 23, 2016

### olivermsun

Check the units on your last line (2)?

3. Oct 23, 2016

### haruspex

Correct.
It says nothing about change in speed.
Magnitude of change of velocity is not the same as change of magnitude of velocity.