Explanation:
Electromagnetic waves are the waves which are created as the result of the electrical waves which are perpendicular to each other and also perpendicular to the direction of propagation.
Electromagnetic spectrum is range of the frequencies and their respective wavelengths of the various type of the electromagnetic radiation.
In order of the increasing frequency and the photon energy and the decreasing wavelength the spectrum are:
radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays and gamma rays.
The energy of the radio waves photons is the lowest of all the other waves in the electromagnetic spectrum.
Also, 
Where,
h is Plank's constant having value 
Thus, energy is directly proportional to the frequency. The radio waves have the lowest frequency.
Answer:
Fnet = 0
Explanation:
- Since the block slides across the floor at constant speed, this means that it's not accelerated.
- According Newton's 2nd Law, if the acceleration is zero, the net force on the sliding mass must be zero.
- This means that there must be a friction force opposing to the horizontal component of the applied force, equal in magnitude to it:

- In the vertical direction, the block is not accelerated either, so the sum of the normal force and the vertical component of the applied force, must be equal in magnitude to the force of gravity on the block:

⇒ 169 N + Fn = Fg = 216 N (3)
- This means that there must be a normal force equal to the difference between Fappy and Fg, as follows:
- Fn = 216 N - 169 N = 47 N (4)
Answer:
Δx = 1.2 m
Explanation:
The CHANGE of spring length) (Δx) can be found using PS = ½kΔx²
Δx = √(2PS/k) = √(2(450)/650) = 1.17669... ≈ 1.2 m
The actual length of the spring is unknown as it varies with material type, construction method, extension or compression, and other variables we have no clue about.
Answer:

Explanation:
Given that,
Initial velocity, u = -5 m/s
Final velocity, v = -22 m/s
Time, t = 3s
We need to find the acceleration of the car. The formula of it is given by :
Acceleration,

So, the acceleration of the car is
.