(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A physics book has a height of 26.0 cm, a width of 22.4 cm, and a thickness of 3.10 cm.

(a) What is the density of the physics book if it weighs 18 N?

??? kg/m3

(b) Find the pressure that the physics book exerts on a desktop when the book lies face up.

??? Pa

(c) Find the pressure that the physics book exerts on the surface of a desktop when the book is balanced on its spine.

??? Pa

2. Relevant equations

Divide the weight by gravity to get the mass.

18N/9.81 = 1.83 kg.

P = F/A

3. The attempt at a solution

Convert cm to meters:

(26.0cm)/100 = 0.26

22.4/100 = 0.224

3.10/100 = 0.031

Now divide

1.83/(0.26*0.224*0.031) = 1.83/0.00180544 = 1014 kg/m^3

P = F/A

area of the book = (0.224*0.26) = 0.5824 m^2

18/0.5824 = 30.9 Pa

When balanced on its spine, its width and thickness make up the area

(0.224*0.0310) = 0.006944

18/0.006944 = 2592 Pa

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