- #1

killazys

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## Homework Statement

The terminal velocity of a [tex]2.8*10^{-5}[/tex]kg raindrop is about 14 m/s.

Determine the time required for such a drop, starting from rest, to reach 63 percent of terminal velocity.

## Homework Equations

[tex]F_{g}-F_{D}=-bv[/tex]

## The Attempt at a Solution

[tex]F_{D}=1.96*10\exp{-5}[/tex]

[tex]mg-b*(0.63V_{T}) = ma\\[/tex]

[tex]mg-bv = m*\frac{dv}{dt}\\[/tex]

[tex]\frac{dt}{m} = \frac{dv}{mg-bv}\\[/tex]

[tex]1/m\int{dt} = \int{\frac{dv}{mg-bv}}\\[/tex]

[tex]\mbox{plugging into calculator}\\[/tex]

[tex]1/m*t=50727.1568[/tex]

.994s

Well, that basically. My physics teacher said that there was no need for calculus, so I'm trying to solve without integrating. There are more questions I have problem with, as always on forums I will first do a search, then post.. should I start a new topic if I can't find a solution?

EDIT: decided to use an integral solution. is that the answer?

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