Please answer this physics question. Its about conservation of mechanical energy.?

Question

Q: A 755 N diver drops from a board 10 m above the water's surface. Find the divers speed 5 m above the waters surface. Then find the divers speed just before striking the water.

Please show me how you got the answer.

Answer 1

Hi

E(initial) = E(final)
KE(initial) + PE(initial) = KE(final) + PE(final)
(1/2)mVi^2 +mgHi = (1/2)mVf^2 + mgHf

the mass, m cancels out of every term,
and Vi is the diver's initial velocity at the top and it is zero (diver has no initial velocity).
So,

gHi = (1/2)Vf^2 + gHf
Vf^2 = 2g(Hi - Hf)
Vf = sqrt{ 2g(Hi - Hf)}

where g=9.8 m/s^2
Hi= 10 m (the initial height of the diver)
and
Hf = whatever value you choose. The problem asks for the velocity at Hf = 5m above the water and Hf = 0m . Zero meters is the point at which the diver strikes the water.

Plug these values into the equation and you should get

at 5m, Vf = 9.899 m/s (this should probably be rounded to 9.9m/s

at 0m, Vf = 14.0 m/s

Notice the fact that the diver weighs 755 N does not enter into the equation.
I hope my notation does not confuse you.

Answer 2

So such as you stated it quite is conservation of mechanical capability, it quite is exciting stuff once you get the carry of it, no rather it quite is! :) So we will initiate off with the hassle-free equation for mechanical capability conservation. (PE + KE)(preliminary)=(PE + KE)very final And all of us recognize that: PE=mgh and KE=.5mv^2 this question differes from the classical conservation of capability difficulty in that our preliminary circumstances have the article moving already, it would not make the priority tougher, merely makes us do a touch greater algebra. i'm going to set the 0 factor for potential capability at factor B, through fact i'm able to. this might make PE(very final)=0 through fact h would be 0. Sooo (PE + KE)(preliminary)=KE(very final) enable's initiate the algebra.. mgh(i) + .5mv^2(i)=.5mv^2(f) We see that there are hundreds in each and all the words so they can cancel them out. gh(i) + .5v^2(i)=.5v^2(f) all of us recognize g, h(i), v(i) So the sole unknown so what we would desire to recognize v(f) so enable's resolve for that. i'm going to initiate by potential of multiplying the two factors by potential of two to get rid that that .5 on the the ideal option hand facet. 2gh(i) + v^2(i)=v^2(f) Then take the sq. root of the two factors to isolate v(f) v(f)=SQRT(2gh + v^2(i)) Now merely plug in some numbers v(f)=SQRT(2*9.8 m/2^s*20m + (8 m/s)^2) Our h is 20 through fact it quite is merely the top distinction between factor A and B v(f)=21.3 m/s In different words Frank ought to easily enable it pass through fact guy..it quite is long previous.

Answer 3

@ 5 m: V^2 = Vo^2 + 2*g*s
where Vo = 0, g = 9.8 m/s^2, s = 5 m

@ 10 m: repeat the above with s = 10 m.