# Pressure on tyres of a vehicle question - Calculating weight

Molly1235

## Homework Statement

The pressure in the tyres of a vehicle is 280 kPa. The contact area of each of the four tyres on the ground is 0.012m^2. Calculate the weight of the vehicle.

## Homework Equations

Force = Pressure x Area

## The Attempt at a Solution

280 kPa = 2800000 Pa

Force = 2800000 x 0.012 = 33,600N

Am I right in assuming that this is the weight of one tyre, so you have to multiply this by 4 to get the force of the whole vehicle on the ground??

I think I've gone completely wrong here so would be grateful for some help!

Thanks :-)

Staff Emeritus
Homework Helper

## Homework Statement

The pressure in the tyres of a vehicle is 280 kPa. The contact area of each of the four tyres on the ground is 0.012m^2. Calculate the weight of the vehicle.

## Homework Equations

Force = Pressure x Area

## The Attempt at a Solution

280 kPa = 2800000 Pa

Force = 2800000 x 0.012 = 33,600N

Am I right in assuming that this is the weight of one tyre, so you have to multiply this by 4 to get the force of the whole vehicle on the ground??

I think I've gone completely wrong here so would be grateful for some help!

Thanks :-)

Double check your conversion of 280 kPa to Pa.

Molly1235
Double check your conversion of 280 kPa to Pa.

Oops - wouldn't it be 280,000 Pa?

Homework Helper
Am I right in assuming that this is the weight of one tyre, so you have to multiply this by 4 to get the force of the whole vehicle on the ground??

Yep!

Oops - wouldn't it be 280,000 Pa?

That looks better! Molly1235
Yep!

That looks better! So my method was correct??

Homework Helper
So my method was correct??

Yes.

Molly1235
Yes.

Yay! Thank you very much!!

• 1 person