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Leo34005
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Homework Statement
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
Homework Equations
Divide the weight by gravity to get the mass.
18N/9.81 = 1.83 kg.
P = F/A
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