Question

You inflate the tires of your car to a gauge pressure of 34.0 lb/in2. If your car has a mass of 1750 kg and is supported equally by its four tires, determine the following.

(a) Contact area between each tire and the road b) Gauge pressure required to give each tire a contact area of 105 cm2

Answer 1

we know, 1 lb/in^2 = 6894.76 pa

so, P_gauge = 34.0 lb/in^2

= 34.0*6894.76

= 234421 pa

given m = 1750 kg

a) let A is the total contact area of four tyres.

so, P_gauge = m*g/A

A = m*g/P_gauge

= 1750*9.8/234421

= 0.07316 m^2

contact area of each tyre = A/4

= 0.07316/4

= 0.0183 m^2 (or) 183 cm^2 <<<<<<<-----------Answer

b) total contact area, A = 4*0.0105

= 0.042 m^2

now use, P_gauge = m*g/A

= 1750*9.8/0.042

= 408333 pa (or) 59.2 lb/in^2 <<<<<<<-----------Answer