Power Dissipation: Understanding Equations & Solutions

[soupastupid]

Homework Statement

Homework Equations

P=F*V

The Attempt at a Solution

why isn't it

P = Cd(A^2)(v^2) * (v)

i don't see what i could do

 

[Doc Al]

Homework Equations

P=F*V

This is correct.

The Attempt at a Solution

why isn't it

P = Cd(A^2)(v^2) * (v)

But this is not. You made an error when you substituted for F in the power equation. Redo it, paying attention to each factor in the drag formula.

 

[soupastupid]

ok i figured out the first part

how do i figure out part B?

I kno the power is proportional to v^3
and so if i increase the power by 10%
i should get

??

if Pi = -(vi^3)AC_d

then 1.1Pi=-(vf^3)AC_d

Pi = (-(vf^3)AC_d ) / 1.1

(vf^3) = 1.1(vi^3)

then what?

 

[Doc Al]

Solve for Vf in terms of Vi. (Take the cube root of both sides.)