Answer:
a) 38"
b) L = 5.7'
Step-by-step explanation:
a) Given
P = 9,500 lb/ft
Thick = 18"
We assume an allowable bearing pressure of σ = 3000 lb/sf
If Stress = Force / Area
σ = P/A
Solving for area
A = P/σ ⇒ A = 9,500 lb/ft/3000 lb/sf
⇒ A = 3.167 sf, or 3.167 ft wide, per foot of length.
⇒ A = 38" wide
We can see the pic 1 in order to understand the answer.
b) Given
P = 65,000 pounds = 65,000 lb
Thick = 18" = 1.5'
We assume an allowable bearing pressure of σ = 2000 lb/sf
If Stress = Force / Area
σ = P/A
Solving for area
A = P/σ ⇒ A = 65,000 lb/2000 lb/sf
⇒ A = 32.5 sf
then A = L² ⇒ L = √A = √(32.5 sf) = 5.7 ft
Finally L = 5.7'
We can see the pic 2 in order to understand the answer.
The length of the rectangle is 3 cm
<h3>Applications of Quadratic equations</h3>
From the question, we are to determine the value of the length of the rectangle
To find the length of the rectangle, we will determine the value of x in the given equation
The given equation is

This can be written as

Factorizing



Then,
OR 
x = 3 OR x = -8
Since, the length of the rectangle cannot be negative, the value of x is 3.
Hence, the length of the rectangle is 3 cm.
Learn more on solving quadratic equations here: brainly.com/question/8649555
Answer:
0
Step-by-step explanation:
Substitute to get 4^2-8/ 4^2 equals 8, 8-8=0
hope this helps