# Tire inflation to determine weight

1. Mar 18, 2006

### BooGTS

Tire inflation to determine weight - solved

The problem goes as follows: he four tires of an automobile are inflated to a gauge pressure of 1.85E+5 Pa. Each tire has an area of 0.0237 m2 in contact with the ground. Determine the weight of the automobile.

But I've applied the Pfluid = F/A and it doesn't seem to pan out. I come up with 447 N per tire, which is wrong.

Last edited: Mar 18, 2006
2. Mar 18, 2006

### Hootenanny

Staff Emeritus
Please show your working. It's hard to see where you've gone wrong if you don't show your working.

3. Mar 18, 2006

### HallsofIvy

Then you done the arithmetic wrong: 2 x 10^5 times 2x 10^(-2)= 4 x 10^3 or 4000, not 400.

4. Mar 18, 2006

### BooGTS

I worked on this problem forever before posting and figured it out in this little window on this site of all places. I'm sure it wont be my last tonight though... thanks for the response.

1. 1.85 x10^5 N/m^2 = (x/.0237m^2)

2. 1.85 x10^5 N x .0237 = 4384.5 N = x

3. 4384.5 N x 4 = 17538N =x

5. Mar 18, 2006

### Hootenanny

Staff Emeritus
Look's good to me

6. Mar 18, 2006

### Curious3141

As Halls of Ivy said, that looks like a simple mathematical error.

Don't forget each tyre only bears a fraction of the weight of the car. So after getting the force exerted by each tyre on the ground, you need to do something else to find the weight of the car.

EDIT : Ah, OK, you've already posted it, that's correct.