help...for our exams this afternoon --fluids?

Question

1. a 200 kg balsa with a volume of 2.00 cubic meter floats on the sea.what is the minimum number of 50 kg people able to board before it sinks?

2. given a drum of water raised to a height H, it develops a crack and water began to get out at velocity v, how can i know the range the water will reach?

These are the list of possible questions...pls. help me...tnx

Answer 1

1. Pw Vb= PbVb + nM
Pw - water density
Pb- balsa density
Vb - Volume of balsa
n- number of people of mass M

n=(Pw Vb - PbVb )/M

2. Start with the Bernoulli's Equation
State equation at the top = State equation at the bottom

P1+ 0.5 pV1^2 + pgh1= P2+ 0.5 pV2^2 + pgh2

P - pressure
p - density of fluid
V -velocity of fluid
h - height

P1=P2
V1=0
V2=?
h1= h
h2=0
we have
pgh1= 0.5 pV2^2

V2= sqrt (2 pgh1/p)
V2= sqrt (2 g h1)