Question

HOW DO I DO THIS PLZ HELP I DON'T NEED U TO SOLVE I JUST NEED TO KNOW HOW

Salmon often jump waterfalls to reach their
breeding grounds.
Starting 2.65 m from a waterfall 0.584 m
in height, at what minimum speed must a
salmon jumping at an angle of 25.2
◦
leave the
water to continue upstream? The acceleration
due to gravity is 9.81 m/s
2
.
Answer in units of m/s

Answer 1

As you know,

y(x) = tanθ x - g/(2 (v*cos^2θ)^2) x^2
For your angle, that gives
y(x) = .47x - 5.99/v^2 x^2

We want this parabola to have a vertex at (2.65,0.584) so since its max is at x=0.039v^2, we need

.039v^2 = 2.65
v = 8.22

Check:

y(x) = .47x - .0886 x^2
has vertex at (2.65,0.623) which is high enough to clear the waterfall.