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Symstar

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## Homework Statement

You dive straight down into a pool of water. You hit the water with a speed of 6.5 m/s, and your mass is 65 kg.

Assuming a drag force of the form [tex]F_D=cv=(-1.2*10^4 \tfrac{kg}{s})*v[/tex], how long does it take you to reach 2% of your original speed? (Ignore any effects of buoyancy.)

## Homework Equations

[tex]ma=F_D-mg[/tex]

[tex]v(t)=v_0+at[/tex]

## The Attempt at a Solution

[tex]ma=F_D-mg[/tex]

[tex]a=\frac{F_D}{m}-g[/tex]

[tex]a=\frac{(-1.2*10^4)*-6.5}{65}-9.8=1190.2[/tex]

[tex]v(t)=v_0+at[/tex]

[tex]-6.5*.02=-6.5+1190.2t[/tex]

[tex]t=5.4*10^{-3}[/tex]

Logically, the answer does not make sense, nor is it correct. Where did I go wrong?

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