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## Homework Statement

A car has four tires in contact with the ground each of which is inflated to an absolute pressure of 3.1×105Nm^-2. If a person of mass 82 kg gets into the car by how much will the total area of contact between the tyres and the ground increase assuming that the tire pressure remains constant?

m = 82kg

P = 3.1×10^5Nm^-2

g = 9.81ms^-2

P(atmosphere)=10^5Nm^-2

## Homework Equations

Pressure, P = F/A

F = ma

## The Attempt at a Solution

The above equation was used in order to get the solution. P = (9.81ms^-2×82kg)/(3.1x10^5Nm^-2)

= .00259 × 4 (number of tires)

= 0.01m^2

This does not give me the correct answer. Do I have to consider atmospheric pressure? If so, are there any more equations required in this problem?