Question

Uca is designing a propeller system that consists of 3 blades, each of which is

identical. The blades are sectors of a circle that have radii of 4 inches and central
rangles of 20" The blades are to be made from steel that weighs 16 grams per square
inch. Determine the weight of the three blades together to the nearest gram.
201​

Answer 1

The weight of the three blades together is
`134\ g`

Explanation:

step 1

Find the area of the circle

The area of the circle is equal to

`A=\pi r^(2)`

we have

`r=4\ in`

assume

`\pi=3.14`

substitute

`A=(3.14)(4)^(2)`

`A=50.24\ in^(2)`

step 2

Find the area of the 3 blades

we know that

The area of the 3 blades represent a central angle of 60 degrees, so

its a 1/6 of the area of complete circle

`A=50.24/6=8.37\ in^(2)`

step 3

Find the weight of the three blades together to the nearest gram

`(8.37\ in^(2))*(16\ g/in^(2))=134\ g`