To solve this problem we will apply the concepts related to the Doppler Effect. The Doppler effect is the change in the perceived frequency of any wave movement when the emitter, or focus of waves, and the receiver, or observer, move relative to each other.
Mathematically it can be described as

Where,
v = Speed of sound
f' = Reflected frequency
f = Emitted Frequency
= Speed of the object
Assuming that the speed of the medium is the speed of sound of 343m / s, we will then have that:


Answer:
The intensity of laser 2 is 4 times of the intensity of laser 1.
Explanation:
The intensity in terms of electric field is given by :

E is electric field
It means, 
In this problem, lasers 1 and 2 emit light of the same color, and the electric field in the beam of laser 1 is twice as strong as the e-field of laser 2.
Let E is electric field in the beam of laser 1 and E' is the electric field in the beam of laser 2. So,

We have,
E'=2E
So,

So, the intensity of laser 2 is 4 times of the intensity of laser 1.
Answer:
m = 28.7[kg]
Explanation:
To solve this problem we must use the definition of kinetic energy, which can be calculated by means of the following equation.

where:
Ek = kinetic energy = 1800 [J]
m = mass [kg]
v = 11.2 [m/s]
![1800=\frac{1}{2}*m*(11.2)^{2}\\m = 28.7[kg]](https://tex.z-dn.net/?f=1800%3D%5Cfrac%7B1%7D%7B2%7D%2Am%2A%2811.2%29%5E%7B2%7D%5C%5Cm%20%3D%2028.7%5Bkg%5D)
Answer:
(A) –14m/s
(B) –42.0m
Explanation:
The complete solution can be found in the attachment below.
This involves the knowledge of motion under the action of gravity.
Check below for the full solution to the problem.
Answer:
Temperature
Explanation:
Heat only flows from one point to the other due to the difference in temperature.