Answer:0.318 revolutions
Explanation:
Given
Initially Propeller is at rest i.e. 
after 

using 


Revolutions turned in 2 s



To get revolution 
=
1. Frequency: 
The frequency of a light wave is given by:

where
is the speed of light
is the wavelength of the wave
In this problem, we have light with wavelength

Substituting into the equation, we find the frequency:

2. Period: 
The period of a wave is equal to the reciprocal of the frequency:

The frequency of this light wave is
(found in the previous exercise), so the period is:

Explanation:
power=f×v. recall= distances/ time
= f× d/t
= 30 × 2/5
=12watt
Answer:
When they are connected in series
The 50 W bulb glow more than the 100 W bulb
Explanation:
From the question we are told that
The power rating of the first bulb is 
The power rating of the second bulb is 
Generally the power rating of the first bulb is mathematically represented as

Where
is the normal household voltage which is constant for both bulbs
So

substituting values

Thus the resistance of the second bulb would be evaluated as

From the above calculation we see that

This power rating of the first bulb can also be represented mathematically as

This power rating of the first bulb can also be represented mathematically as

Now given that they are connected in series which implies that the same current flow through them so

This means that

So when they are connected in series

This means that the 50 W bulb glows more than the 100 \ W bulb
The net force on a 0.50-cm-diameter eardrum is mathematically given as
F= 0.76969 N
<h3>What is the net force on a 0.50-cm-diameter eardrum?</h3>
Generally, the equation for Pressure is mathematically given as
P = ρgh
Therefore
P= 1000*9.8*4
P= 39200 Pa
Where
A= pi*(0.005/2)^2
Generally, the equation for Net force is mathematically given as
F = PA
F= 39200 *( pi*(0.005/2)^2)
F= 0.76969 N
In conclusion, The net force is
F= 0.76969 N
Read more about Pressure
#SPJ1