# What is the magnitude of the car's displacement

1. Sep 16, 2004

### Catgirl-Pink

I've got a problem I can't seem to figure out.."A certain car is capable of accelerating at a uniform rate of 0.85 m/s^2 (<-- squared). What is the magnitude of the car's displacement as it accelerates uniformly from a speed of 83 km/h to one of 94 km/h? "(Note: in my book we use vi= initial velocity ,vf=final velocity, a=acceleration, delta t=time interval and delta x = displacement) I think I'm supposed to use the equation vf^2= vi^2 + 2a(delta x)....I might have to rearrange it..I'm not sure..

Last edited by a moderator: Sep 15, 2015
2. Sep 16, 2004

### Integral

Staff Emeritus
The first step will be to determine how long (the time) it takes to accelerate to you max speed. Given that time and the relationship that tells you how far you travel under constant acceleration from an initial velocity, you can compute how far you have traveled.

EDIT: It has been pointed out that my approach is not the only possible one. You may well have at your disposal a single equation which will provide the solution. You will find that very frequently the key information in this type of problem is the time. I am a creature of habit, I simply do what I know will work.

Last edited: Sep 16, 2004
3. Sep 16, 2004

### Gokul43201

Staff Emeritus
You're right about the equation to use.

There's one more thing to keep in mind : UNITS. You need to use the same units throughout, so convert km/hr to m/s before substituting into the equation.

Last edited: Sep 16, 2004