The glass in a window is 35 inches wide and 20 inches tall, and standard atmospheric pressure is 14.7 pounds per square inch. What net force would result on the glass if the air pressure outside the house were 1% lower than the air pressure inside?
A) 103 pounds inward.
B) 103 pounds outward.
C) 10300 pounds inward.
D) 10300 pounds outward.
E) There would be no net force.

Question

Quizplus · Accepted Answer

The net force is calculated by finding the difference in pressure between the inside and outside of the house and then multiplying this by the area of the glass. A 1% decrease in pressure from 14.7 psi results in an external pressure of 14.553 psi (14.7 - 0.147 = 14.553 psi). The area of the glass is 35 inches * 20 inches = 700 square inches. The pressure difference is 0.147 psi (14.7 - 14.553), so the net force is 0.147 psi * 700 square inches = 102.9 pounds, rounded to 103 pounds. Since the pressure outside is lower, the net force is outward.

The Glass in a Window Is 35 Inches Wide and 20