Answer:
Vi = 32 [m/s]
Explanation:
In order to solve this problem we must use the following the two following kinematics equations.

The negative sign of the second term of the equation means that the velocity decreases, as indicated in the problem.
where:
Vf = final velocity = 8[m/s]
Vi = initial velocity [m/s]
a = acceleration = [m/s^2]
t = time = 5 [s]
Now replacing:
8 = Vi - 5*a
Vi = (8 + 5*a)
As we can see we have two unknowns the initial velocity and the acceleration, so we must use a second kinematics equation.

where:
d = distance = 100[m]
(8^2) = (8 + 5*a)^2 - (2*a*100)
64 = (64 + 80*a + 25*a^2) - 200*a
0 = 80*a - 200*a + 25*a^2
0 = - 120*a + 25*a^2
0 = 25*a(a - 4.8)
therefore:
a = 0 or a = 4.8 [m/s^2]
We choose the value of 4.8 as the acceleration value, since the zero value would not apply.
Returning to the first equation:
8 = Vi - (4.8*5)
Vi = 32 [m/s]
Use v = u + at
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Answer:
Option (C)
Explanation:
The nuclear energy is defined as a type of energy which liberates either by the process of nuclear fusion or nuclear fission and is mainly used to generate electricity. This energy is stored in the core of an atom (or nucleus).
It is highly effective, cost-effective and there is no emission of greenhouse gases.
But it also has some disadvantages, of which one is that it produces radioactive waste materials, which are difficult to dispose these substances and is also a very expensive method. These materials emit radiations that are harmful to the organisms. So, it is very challenging to dispose these radioactive waste materials.
Thus, the correct answer is option (C).