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2 years ago

Which of the following electromagnetic waves is not used for communication?

1 answer:

8 0

Microwaves and radio waves are employed in radio and satellite communications while infrared waves are used in remote controls and infrared features of new phones and other electrons. However, gamma rays have far too much energy and cause damage to the body. They are not used in communication.
The answer is A.

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A football punter accelerates a .55 kg football

Ronch [10]

Answer:

17.6 N

Explanation:

The force exerted by the punter on the football is equal to the rate of change of momentum of the football:

$F=\frac{\Delta p}{\Delta t}$

where

$\Delta p$ is the change in momentum of the football

$\Delta t=0.25 s$ is the time elapsed

The change in momentum can be written as

$\Delta p = m(v-u)$

where

m = 0.55 kg is the mass of the football

u = 0 is the initial velocity (the ball starts from rest)

v = 8.0 m/s is the final velocity

Combining the two equations and substituting the values, we find the force exerted on the ball:

$F=\frac{m(v-u)}{\Delta t}=\frac{(0.55)(8.0-0)}{0.25}=17.6 N$

5 0

3 years ago

At the equator, the radius of the Earth is approximately 6370 km. A plane flies at a very low altitude at a constant speed of v

Anna007 [38]

To solve this problem we will apply the concepts related to the kinematic equations of linear motion. For this purpose we will define the speed as the distance traveled in a given period of time. Here the distance is equivalent to the orbit traveled around the earth, that is, a circle. Approaching the height of the aircraft with the radius of the earth, we will have the following data,

$R= 6370*10^3 m$

$v = 219m/s$

$a = 17m/s^2$

The circumference of the earth would be

$\phi = 2\pi R$

Velocity is defined as,

$v = \frac{x}{t}$

$t = \frac{x}{v}$

Here $x = \phi$ , then

$t = \frac{\phi}{v} = \frac{2\pi (6370*10^3)}{219}$

$t = 1.82*10^5s$

Therefore will take $1.82*10^5$ s or 506 hours, 19 minutes, 17 seconds

3 0

2 years ago

PLEASE HELP ASAP!! THIS IS DUE IN 15 MUNITES!! Explain what a Precipitate (Not Precipitation) is and tell me if it is a Physical

Amiraneli [1.4K]

Answer:

A precipitate is a solid that separates out of a liquid solution when it is supersaturated (insoluble). This is a chemical change.

Explanation:

Precipitation is when a chemical substance converts into a solid from a solution by converting the substance into an insoluble form or a super-saturated solution. When the reaction occurs in a liquid solution, the solid formed is called the precipitate.

Hope that helps.

3 0

2 years ago

Is the bike rider in the picture above demonstrating kinetic energy or potential energy? you need to explain your answer.

soldi70 [24.7K]

Answer:

Kinetic energy

Explanation:

Kinetic energy is a function of velocity. Since the rider is moving at a certain speed, he's demonstrating kinetic energy. It can't be potential energy because potential energy encompass mgh

4 0

3 years ago

What is harmonic oscillation

inn [45]

Explanation:

A simple harmonic oscillation is an oscillator that is neither driven nor damped.

3 0

2 years ago