Question

The force F of the wind on a flat surface positioned at a right angle to the direction of the wind varies jointly with both the area A of the surface and the square of the speed v of the wind. A wind of 30 miles per hour blowing on a window that that has a surface area of 20 square feet has a force of 150 pounds. What is the force on a window that has a surface area of 12 square feet caused by a wind of 50 miles per hour?

Answer 1

isnt the formula y=kxz??

Answer 2

close

Answer 3

but isnt it jointly

Answer 4

"The force F of the wind on a flat surface positioned at a right angle to the direction of the wind varies jointly with both the area A of the surface and the square of the speed v of the wind. "

all translates to

F = kAv^2

Answer 5

the formula you wrote is very similar, it's just using different variables

Answer 6

oh ok go on

Answer 7

"A wind of 30 miles per hour blowing on a window that that has a surface area of 20 square feet has a force of 150 pounds"

means what?

Answer 8

in terms of the variables given

Answer 9

30=v,20=a

Answer 10

Good, v = 30 and A =20, what is F in that sentence?

Answer 11

150

Answer 12

so we know that when A = 20 and v = 30, then F = 150

So

F = kAv^2

becomes

150 = k*20*(30)^2

Answer 13

Solve for k

Answer 14

i dont get a logical answer

Answer 15

tell me what you get

Answer 16

k=1/120

Answer 17

good

Answer 18

so

F = kAv^2

becomes

F = (1/120)Av^2

which is the same as

F = (Av^2)/(120)

Answer 19

Last part:

What is the force on a window that has a surface area of 12 square feet caused by a wind of 50 miles per hour?


So you just plug A = 12 and v = 50 into that last equation to find F

Answer 20

250lbs

Answer 21

could you help me with the other ones i sent you??

Answer 22

good, I'm getting that as well

Answer 23

post them as questions please

Answer 24

ill post them

Answer 25

ok