Answer:
The mass will be "8.86 lb".
Explanation:
The given values are:
Force
= 70,000 mi/h
Speed
= 7900 mi/h
On applying the Law of momentum, we get
⇒ 
On putting the estimated values, we get
⇒ 
⇒ 
⇒ 
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.
Explanation:
Below is an attachment containing the solution.
Given:
Ca = 3Cb (1)
where
Ca = heat capacity of object A
Cb = heat capacity f object B
Also,
Ta = 2Tb (2)
where
Ta = initial temperature of object A
Tb = initial temperature of object B.
Let
Tf = final equilibrium temperature of both objects,
Ma = mass of object A,
Mb = mass of object B.
Assuming that all heat exchange occurs exclusively between the two objects, then energy balance requires that
Ma*Ca*(Ta - Tf) = Mb*Cb*(Tf - Tb) (3)
Substitute (1) and (2) into (3).
Ma*(3Cb)*(2Tb - Tf) = Mb*Cb*(Tf - Tb)
3(Ma/Mb)*(2Tb - Tf) = Tf - Tb
Define k = Ma/Mb, the ratio f the masses.
Then
3k(2Tb - Tf) = Tf - Tb
Tf(1+3k) = Tb(1+6k)
Tf = [(1+6k)/(1+3k)]*Tb
Answer:

where
When light hits the boundary between two different materials, it can undergo both reflection and refraction.
Reflection is the change in the direction of the
wave that strikes the boundary between two materials.<span> It involves a change in the direction of waves when they clash with an obstacle.
Refraction involves the change in the direction of waves as they move from one medium to </span><span><span>another followed</span></span><span> by a change in speed and wavelength (this second medium should have different permitivity for the light to change its initial properties.)</span>