Refractive index (symbol n) is defined as the ratio of the velocity of light in a vacuum (symbol c) to the velocity of light in a medium (symbol v). The equation is n=c/v. In order to obtain the speed of light in carbon disulphide the above equation needs to be rearranged to make v the subject. This yields v=c/n. Plugging the numbers in yields a speed to 1.84x10^8 metres per second.
Answer:
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<u><em>Answer</em></u>
A) 1,347.5 Joules
B) 22.49 m/s
<u><em>Explanation</em></u>
<u>Part A</u>
The work done by the gravity is known as potential energy.
It is given by;
P.E = mgh
Where m is mass, g is acceleration due to gravity and h is the vertical height.
P.E = 5.5 × 9.8 ×25
= 1,347.5 Joules.
<u>Part B</u>
Using the Newton's third Law of motion,
V² = U² +2as
Where v is final velocity, u is the initial velocity, and s is the displacement of the stone.
V² = 4² + (2×9.8×25)
= 16 + 490
= 506
V = √506
= 22.49 m/s
False....................................
