Answer to Question #144543 in General Chemistry for JM

Question

The four tyres of a car are inflated to a gauge pressure of 200 kPa. Each tyre has an area of 0.015 m2 in contact with the road.

a. what is the weight of the car?

b. if the pressure in the tyres has been reduced to 150 kPa, what is the area of contact of each tyre with the road?

Answer 1

General Chemistry

The four tyres of a car are inflated to a gauge pressure of 200 kPa. Each tyre has an area of 0.015 m2 in contact with the road.

a. what is the weight of the car?

           Total area of the four tires of the car A = 4 x 0.015

           = 0.06m²

           = Gauge pressure P = 200 kPa

           = 200 kN/m²

               Therefore, the force on the tires F = PA

           = 200 kN/m² x 10³ N/m² x 0.06m²

               = 1200N

           Henceforth, the weight of the car

           W = 1200N

b. if the pressure in the tyres has been reduced to 150 kPa, what is the area of contact of each tyre with the road?

           New are of the four tires A = F/P

           A = 1200N/150 x 10³ N/m²

           A = 0.008m²

               Area of each tire = 0.008/4

           Area = 0.002m²