tuti drops a marble into a 20 m deep well g=10 m/s^2. what is the time needed by the marble to reach the surface of water in the well?

Question

abhisar · Answer

u=0
s=20
a=10

use the same formula we used in the last question and find the value of t

anonymous · Answer

I thought using the vt^2=2gh formula for this one, am i mistaken? physics is a bit confusing, and there are no proper information in my module

abhisar · Answer

But you don't know the value of v, so u can't use this formula here.

anonymous · Answer

Right... Thanks..

abhisar · Answer

use $\sf huge s=ut+\frac{1}{2}at^2$
answer will be 4seconds

anonymous · Answer

I got 5 seconds

abhisar · Answer

20=0*t+0.5*10*$\sf t^2$
=>$\sf t^2$=4
=>t=2 seconds

abhisar · Answer

Sorry answer will be 2 seconds

anonymous · Answer

okay thanks