An airtight box, having a lid of area 80.0 cm², is partially evacuated.Atmospheric pressure is 1.01 x 10⁵ Pa.A force of 108 lb is required to pull the lid off the box.The pressure in the box was: A)1.35 x 10⁴ Pa B)2.60 x 10⁴ Pa C)4.10 x 10⁴ Pa D)8.75 x 10⁴ Pa E)1.36 x10⁵ Pa

Question

Quizplus · Accepted Answer

First, we need to calculate the weight of the lid:

weight = force x gravity 
weight = 108 lb x 4.45 N/lb (conversion factor) 
weight = 481.8 N

Next, we can use the following formula to find the pressure inside the box:

pressure = (weight of lid) / (area of lid) - (atmospheric pressure)

Since the lid is partially evacuated, we can assume that the pressure inside the box is lower than atmospheric pressure, and we subtract it from the weight of the lid.

pressure = (481.8 N) / (0.008 m^2) - (1.01 x 10^5 Pa) 
pressure = 6.0225 x 10^5 Pa - 1.01 x 10^5 Pa 
pressure = 5.0125 x 10^5 Pa 
pressure = 4.10 x 10^4 Pa 
pressure = 4.10 x 10^-2 MPa

Therefore, the answer is (C) 4.10 x 10^4 Pa.

An Airtight Box, Having a Lid of Area 80