when observer and source moves relative to each other then the frequency received by the observer is different from the real frequency
This apparent change in frequency due to relative motion is known as Doppler's effect.
Here we know that

here we know that
= real frequency
v = speed of sound
= speed of observer
= speed of source
so this is known as Doppler's Effect
Electrons are important to the electric current because they are able to move from one atom to another. When an atom loses an electron, it becomes positively charged and when an atom gains an electron, it becomes negatively charged.
Answer: 
Explanation:
Given
Power 
Distance from the light source 
Intensity is given by

Inserting values

Answer:
16.87 m/s
Explanation:
To find the speed of the car at the top, when the normal force is equal the gravitational force, we just need to equate both forces:


is the centripetal acceleration in the loop:

So we have that:




So, using the gravity = 9.81 m/s^2 and the radius = 29 meters, we have:


The speed of the car is 16.87 m/s at the top.
Centripetal force is defined as, "the force that is necessary to keep an object moving in a curved path and that is directed inward toward the center of rotation," while centrifugal force is defined as "the apparent force that is felt by an object moving in a curved path that acts outwardly away from the center of rotation," according to Merriam Webster Dictionary.