The answer is actually as temperature decreases the speed of sound decreases. "As temperature decreases, the speed of sound decreases. As pressure, or oceanic depth, increases, the speed of sound increases." - my book.
Potential energy is stored an object , where as kinetic energy is energy in a object during movement . Potential energy is what kinetic energy transfers into
Answer : The half-life of this substance will be, 45 minutes.
Explanation :
First we have to calculate the value of rate constant.
Expression for rate law for first order kinetics is given by:

where,
k = rate constant = ?
t = time passed by the sample = 90.3 min
a = initial amount of the reactant = 400
a - x = amount left after decay process = 100
Now put all the given values in above equation, we get


Now we have to calculate the half-life of substance, we use the formula :



Therefore, the half-life of this substance will be, 45 minutes.
By studying meteorites which are the most ancient material in space.
Answer:
The overall velocity of the water when it hits the bottom is:

Explanation:
Use the law of conservation of energy.
Call it instant [1] to the moment when the water is just before reaching the falls.
At this moment its height h is 206 meters and its velocity horizontally
is
m/s.
At the instant [1] the water has gravitational power energy 

The water also has kinetic energy Ek.

Then the Total E1 energy is:

In the instant [2] the water is within an instant of touching the ground. At this point it only has kinetic energy, since the height h = 0. However at time [2] the water has maximum final velocity 
So:

As the energy is conserved then 

Now we solve for
.
