A friend asks you how much pressure is in your car tires. You know that the tire
ID: 1476713 • Letter: A
Question
A friend asks you how much pressure is in your car tires. You know that the tire manufacturer recommends 35 psi , but it's been a while since you've checked. You can't find a tire gauge in the car, but you do find the owner's manual and a ruler. Fortunately, you've just finished taking physics, so you tell your friend, "I don't know, but I can figure it out." From the owner's manual you find that the car's mass is 2200 kg . It seems reasonable to assume that each tire supports one-fourth of the weight. With the ruler you find that the tires are 16 cm wide and the flattened segment of the tire in contact with the road is 16 cm long.
What answer will you give your friend?
Explanation / Answer
mass of the car m=2200 kg
weight of the car, w=m*g
w=2200*9.8
w=21560 N
weight on each tire of the car is w'=21560/4
w'=5390 N
contact area A=(16*16)*10^-4 m^2
and
pressure in each tire is,P=w'/A
P=5390/((16*16)*10^-4)
P=210546.875 N/m^2
P=30.54 psi =========> is answer