Complete Question
The complete question is is shown on the first uploaded
Answer:
The elastic potential energy at point B is
The kinetic energy at point D is 
Explanation:
Looking at the given point we can observe that mechanically energy(i.e potential and kinetic energy ) is conserved and it value is 
So at point B


KE at point B is 50J
So 
Now at point D

at point D is 25J
So 
Answer:
Amplitude, A = 0.049 meters
Explanation:
Given that,
A harmonic wave travels in the positive x direction at 6 m/s along a taught string. A fixed point on the string oscillates as a function of time according to the equation :
.......(1)
The general equation of a wave is given by :
.......(2)
A is amplitude of wave
On comparing equation (1) and (2) we get :
A = 0.049 meters
So, the amplitude of the wave is 0.049 meters.
Answer:
Part a)

Part b)

Part c)

Explanation:
Part a)
The height of the diving board is given as

now the speed of the diver is given as

when the diver will jump into the water then his displacement in vertical direction is same as that of height of diving board
So we will have



Part b)

plug in the values in the above equation


Part c)
Horizontal distance moved by the diver is given as



so the distance from the edge of the pool is given as


The answers are:
a) 
b) 
Why?
It seems that you forgot to write the questions of the problem, however, in order to help you, I will try to complete it.
The questions are:
a) How much work does the heart do in a day?
b) What is its power output in watts?
So, solving we have:
We need to convert from liter to cubic meters in order to use the given information, so:

Also, we need to find the mass given the density of the blood.

Now, calculating how much work does the heart do in a day, we have:

Then, calculating what is the power output and its horsepower, we have:

Have a nice day!
Answer: Option (A) is the correct answer.
Explanation:
Convection is a process in which heat transfers from a hotter substance to a colder substance.
As a result, the substance which is less dense will rise and the more denser substance will sink due to the influence of gravity.
Thus, we can conclude that in the given situation substance X will rise due to convection.