Answer:
Time to pass the train=0.05 h
How far the car traveled in this time=4.75 Km
Explanation:
We have that the train and the car are moving in the same direction, the difference between the speed of the vehicles is:

We will use this difference in the speed of the car an train to calculate how much time take the car to pass the train. For this we have that the train is 1km long and the car is moving with a speed of 20km/h (we use this value because is the speed that the car have in advantage of the train) then for a movement with a constant speed we have:

Where x is the distance, t is the time and v is the speed. using the data that we have:

This is the time that the car take to pass the train. Now to calculate how far the car have traveled in this time we have to considered the speed of 95Km/h of the car, then:

The three properties of electromagnetic waves are; they travel at the speed of light, they include ultraviolet waves, and they can transfer energy through empty space.
<h2>Further Explanation</h2><h3>A wave</h3>
- A wave is a transmission of a disturbance. It involves transmission of energy from one point which is the source to another point.
- Waves may be classified depending on the need for a transmission medium or based on the vibration of particles relative to the direction of wave motion.
- Waves may be either transverse or longitudinal based on the direction of wave motion relative to the vibration of particles
- Additionally waves may be classified as either electromagnetic wave or mechanical based on the need for a transmission medium.
<h3>Electromagnetic waves </h3>
- Electromagnetic waves are types of waves that do not require a material medium for transmission.
- All waves of the electromagnetic spectrum are electromagnetic transverse waves that do not require a material medium for transmission.
- They include; radio waves, microwaves, infrared, visible light, ultra-violet, x-rays, and gamma rays.
- All waves of the electromagnetic spectrum travel with a speed of light, 3.0 x10^8 m/s.
- Additionally, electromagnetic waves possess energy that is given by; E = hf; where h is the plank's constant and f is the frequency.
keywords: Wave, electromagnetic wave, electromagnetic spectrum
<h2>Learn more about: </h2>
Level: High school
Subject: Physics
Topic: Electromagnetic spectrum
Sub-topic: Properties of an electromagnetic waves
Answer:
Explanation:
Let the equilibrium position of third charge be x distance from q₁.
Force on third charge due to q₁
= 9 x 10⁹ x 5 x 10⁻⁹ x 15 x 10⁺⁹ / x²
Force on third charge due to q₂
= 9 x 10⁹ x 2 x 10⁻⁹ x 15 x 10⁺⁹ /( .40-x)²
Both the force will act in opposite direction and for balancing , they should be equal.
9 x 10⁹ x 5 x 10⁻⁹ x 15 x 10⁺⁹ / x² = 9 x 10⁹ x 2 x 10⁻⁹ x 15 x 10⁺⁹ /( .40-x)²
5 / x² = 2 / ( .4 - x )²
Taking square root on both sides
2.236 / x = 1.414 / .4 - x
2.236 ( .4 - x ) = 1.414 x
.8944 - 2.236 x = 1.414 x
.8944 = 3.65 x
x = .245 m
24.5 cm
So the third charge should be at a distance of 24.5 cm from q₁ .
I<span>n </span>direct current<span> (</span>DC), the electric charge (current<span>) only flows in one direction. Electric charge in </span>alternating current<span> (</span>AC<span>), on the other hand, changes direction periodically. The voltage in </span>AC<span> circuits also periodically reverses because the </span>current<span> changes direction.</span>
To develop this problem we will apply the considerations made through the concept of 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. At first the source is moving towards the observer. Than the perceived frequency at first

Where F is the actual frequency and v is the velocity of the ambulance
Now the source is moving away from the observer.

We are also so told the perceived frequency decreases by 11.9%



Equating,





Solving for V,
