Answer:
0.20kg-m^2
Explanation:
Let the linear velocity of the rope(=of pulley) is v m/s
Using kinematic equation
=> v = u + at
=>v = 0 + 4.9a
=>v = 4.9a ------------ eq1
By v^2 = u^2 + 2as
=>v^2 = 0 + 2 x v/4.9 x 1.2
=>4.9v^2 - 2.4v = 0
=>v(4.9v - 2.4) = 0
=>v = 2.4/4.9 = 0.49 m/s
Thus by v = r x omega
=>omega = v/r = 0.49/0.02 = 24.49 rad/sec
BY W = F x s = 50 x 1.2 = 60 J
=>KE(rotational) = W = 1/2 x I x omega^2
=>60 = 1/2 x I x (24.49)^2
=>I = 0.20 kg-m^2
Oil is optically denser than water. When sound/light goes from optically denser medium to optically rarer medium, their velocity increase and they moves away for normal.
<h3>
<u>Appropriate</u><u> </u><u>Answer</u><u>:</u></h3>
The sound wave speeds up and bends

As, In optics we learnt that light undergoes refraction when travels from medium of different densities. Similarly, Sound also follows the law of refraction.
- It is due to the change of speed of water in different mediums, This makes it speed up or down depending upon the medium and their densities.
<u>━━━━━━━━━━━━━━━━━━━━</u>
Answer:
η = 1.31
Explanation:
The formula for the refractive index of from air to some other medium is given by the following formula:

where,
η = refractive index = ?
c = speed of light in air = 3 x 10⁸ m/s
v = speed of light in ice = 2.29 x 10⁸ m/s
Therefore, using these values in the equation we get:

<u>η = 1.31</u>
Answer:
Rhythmic Gymnastics
Explanation:
In general, the judges in the sports tend to be in charge for correcting and controlling the breaking of the rules in the particular sport. They are allowed to punish the competitors in accordance with the breaking of the rule, or they are there in order to determine weather a point is regular or not. In the rhythmic gymnastics though, and sports similar to it, the judges have different role, as they are in charge of determining the points earned by the competitors. This is done in a manner where every judge gives certain amount of points, or grades, and when those are summed up, the competitors get their total points.
-- Speed = (distance) / (time to cover the distance) = 840/2.5 = 336 m/s
-- Frequency = (speed) / (wavelength) = 336/0.70 = 480 Hz.