The pressure in car tires is often measured in pounds per square inch (lb/in.2), with the recommended pressure being in the range of 25 to 45 lb/in.2. Suppose a tire has a pressure of 30.0 lb/in.2. Convert 30.0 lb/in.2 to its equivalent in atmospheres. Express the pressure numerically in atmospheres.

2.05 atm

Explanation:

The pressure exerted by a force is equal to the rate between the force exerted and the area over which the force is exerted:

where

p is the pressure

F is the force

A is the area

In this problem, we have the pressure written as

First, we need to convert this into SI units (Newton over squared meters, which is Pascal).

We have:

1 lb = 4.45 N

So the pressure converted into SI units is

Now we know that 1 atmosphere is equivalent to

So we can convert this pressure into atmospheres:

it is the most commonly accepted one