The correct answer is Option C) Sample C would be best, because the percentage of the energy in an incident wave that remains in a reflected wave from this material is the smallest.
As the coefficient of absorption would define the energy present in the reflected wave, the material C has the highest percentage of absorption i.e. 62% and would be best suitable to make a sound proof room.
Answer:
Part a)

Part b)

Part c)

Part d)

Part e)

Explanation:
Part a)
Angular speed is given as



Part b)
Since turn table is accelerating uniformly
so we will have




Part c)
angular acceleration is given as



Part d)
When its angular speed changes to 120 rpm
then we will have


number of turns revolved is 15 times
so we have



Part e)
now for uniform acceleration we have



<span>As seen by Barbara, Neil is traveling at a velocity of 6.1 m/s at and angle of 76.7 degrees north from due west.
Let's assume that both Barbara and Neil start out at coordinate (0,0) and skate for exactly 1 second. Where do they end up?
Barbara is going due south at 5.9 m/s, so she's at (0,-5.9)
Neil is going due west at 1.4 m/s, so he's at (-1.4,0)
Now to see Neil's relative motion to Barbara, compute a translation that will place Barbara back at (0,0) and apply that same translation to Neil. Adding (0,5.9) to their coordinates will do this.
So the translated coordinates for Neil is now (-1.4, 5.9) and Barbara is at (0,0).
The magnitude of Neil's velocity as seen by Barbara is
sqrt((-1.4)^2 + 5.9^2) = sqrt(1.96 + 34.81) = sqrt(36.77) = 6.1 m/s
The angle of his vector relative to due west will be
atan(5.9/1.4) = atan(4.214285714) = 76.7 degrees
So as seen by Barbara, Neil is traveling at a velocity of 6.1 m/s at and angle of 76.7 degrees north from due west.</span>
<h2>
Answer:</h2><h2>
The acceleration of the meteoroid due to the gravitational force exerted by the planet = 12.12 m/
</h2>
Explanation:
A meteoroid is in a circular orbit 600 km above the surface of a distant planet.
Mass of the planet = mass of earth = 5.972 x
Kg
Radius of the earth = 90% of earth radius = 90% 6370 = 5733 km
The acceleration of the meteoroid due to the gravitational force exerted by the planet = ?
By formula, g = 
where g is the acceleration due to the gravity
G is the universal gravitational constant = 6.67 x

M is the mass of the planet
r is the radius of the planet
Substituting the values, we get
g = 
g = 12.12 m/
The acceleration of the meteoroid due to the gravitational force exerted by the planet = 12.12 m/
Answer:
vBxf = 0.08625m/s
Explanation:
This is a problem about the momentum conservation law. The total momentum before equals the total momentum after.

pf: final momentum
pi: initial momentum
The analysis of the momentum conservation is about a horizontal momentum (x axis). When the quarterback jumps straight up, his horizontal momentum is zero. Then, after the quarterback throw the ball the sum of the momentum of both quarterback and ball must be zero.
Then, you have:
(1)
mQ: the mass of the quarterback = 80kg
mB: the mass of the football = 0.43kg
(vQx)i: the horizontal velocity of quarterback before throwing the ball = 0m/s
(vBx)i: the horizontal velocity of football before being thrown = 0m/s
(vQx)f: the horizontal velocity of quarterback after throwing the ball = ?
(vBx)f: the horizontal velocity of football after being thrown = 15 m/s
You replace the values of the variables in the equation (1), and you solve for (vBx)f:

Where you have taken the speed of the quarterback as negative because is in the negative direction of the x axis.
Hence, the speed of the quarterback after he throws the ball is 0.08625m/s