Answer:
velocity = 472 m/s
velocity = 52.4 m/s
Explanation:
given data
steady rate = 0.750 m³/s
diameter = 4.50 cm
solution
we use here flow rate formula that is
flow rate = Area × velocity .............1
0.750 =
× (4.50×
)² × velocity
solve it we get
velocity = 472 m/s
and
when it 3 time diameter
put valuer in equation 1
0.750 =
× 3 × (4.50×
)² × velocity
velocity = 52.4 m/s
here we can say that there is no external force on fisherman and dock
so here we will use momentum conservation theory
As per momentum conservation
initial momentum of fisherman + boat = final momentum of fisherman + boat

now we will have



so the speed of boat and fisherman will be 1.16 m/s
3.85 pounds is the answer