Question

Printed on the side of a tire on an all-wheel-drive sport utility wagon is the warning “Do not inflate above 44 psi,” where psi is the abbreviation for the pressure unit pounds per square inch (lb/in²). Express the tire’s maximum pressure rating in

(a) The USCS unit of lb/ft² (psf) and

 

(b) the SI unit of kPa.

Answer 1

(a)

Number of inches for unit feet is,

1 ft = 12 in

 

Convert 44 lb/in² into units of lb/ft².

(44 lb/in²) × {12²(in/ft)²} = 6336 lb/ft²

 

Therefore the pressure in pounds per square feet is 6336 lb/ft².

 

(b)

The pounds per square inch for unit kilo Pascal pressure is,

1kPa = 0.1450 psi

 

Convert 44 lb/in² into units of kpa.

(44 psi) × (1 kPa/0.1450) = 303.45 kPa

 

 

Therefore the pressure in kPa is 303.45 kPa.

(a) 6336 lb/ft²

(b)  303.45 kPa