# Pressure on tyres of a vehicle question - Calculating weight

• Molly1235
In summary, the pressure in the tyres of a vehicle is 280 kPa and the contact area of each tyre on the ground is 0.012m^2. Using the formula Force = Pressure x Area, the weight of the vehicle can be calculated by converting 280 kPa to 280,000 Pa and then calculating the force as 280,000 x 0.012 = 33,600N. This is the weight of one tyre, so it must be multiplied by 4 to get the total force of the vehicle on the ground. Therefore, the weight of the vehicle is 134,400N.

## 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 :-)

Molly1235 said:

## 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.

SteamKing said:
Double check your conversion of 280 kPa to Pa.

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

Molly1235 said:
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!

Molly1235 said:
Oops - wouldn't it be 280,000 Pa?

That looks better!

I like Serena said:
Yep!

That looks better!

So my method was correct??

Molly1235 said:
So my method was correct??

Yes.

I like Serena said:
Yes.

Yay! Thank you very much!

1 person

## 1) What is the formula for calculating the weight on tyres of a vehicle?

The formula for calculating the weight on tyres of a vehicle is weight = pressure x area, where pressure is the air pressure in the tyre and area is the contact area of the tyre on the ground.

## 2) How does air pressure affect the weight on tyres of a vehicle?

The air pressure in a tyre directly affects the weight on the tyre. As air pressure increases, the contact area of the tyre on the ground decreases, resulting in a higher weight on the tyre. Conversely, as air pressure decreases, the contact area increases, resulting in a lower weight on the tyre.

## 3) How do I determine the correct air pressure for my vehicle's tyres?

The correct air pressure for a vehicle's tyres can typically be found in the owner's manual or on a sticker located on the driver's side door jamb. It is important to follow the manufacturer's recommended air pressure for optimal performance and safety.

## 4) How does the weight on tyres affect a vehicle's handling and fuel efficiency?

The weight on tyres can greatly impact a vehicle's handling and fuel efficiency. An under-inflated tyre can result in decreased fuel efficiency and reduced handling, while an over-inflated tyre can lead to poor handling and uneven tread wear.

## 5) Can the weight on tyres vary depending on the type of vehicle?

Yes, the weight on tyres can vary depending on the type of vehicle. For example, a larger vehicle such as a truck or SUV will have a higher weight on the tyres compared to a smaller car due to its heavier weight and larger contact area on the ground.