MHB Mechanics- general motion in a straight line

[Shah 72]

I don't know how to calculate this. Pls help

 

[skeeter]

$s = 4t^2 - \sqrt{2t^3}$

have you learned any calculus, specifically derivatives?

 

[Shah 72]

$s = 4t^2 - \sqrt{2t^3}$

have you learned any calculus, specifically derivatives?

Yeah so ds/dt=8t-3sqroot(2t)/2

 

[Shah 72]

$s = 4t^2 - \sqrt{2t^3}$

have you learned any calculus, specifically derivatives?

I have tried doing this so ds/dt=v
13= 8t-3sqroot (2t)/2

 

[Shah 72]

$s = 4t^2 - \sqrt{2t^3}$

have you learned any calculus, specifically derivatives?

So I get quadratic equation. I got t=2s. Thank you very much!