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3 years ago

Radio waves and microwaves are similar because they both have

Physics

1 answer:

tekilochka [14]3 years ago

4 0

The correct answer is

b. low frequencies and low energy.

In fact, microwaves and radio waves have frequency up to $10^{10}-10^{11} Hz$ , which are really low compared, for instance, to the frequency of gamma rays ( $10^{20} Hz$ ). Moreover, the energy of an electromagnetic wave is directly proportional to its frequency:

$E=hf$

where h is the Planck constant and f the frequency; therefore, low frequency means also low energy.

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The tub of a washer goes into its spin-dry cycle, starting from rest and reaching an angular speed of 5.0 rev/s in 8.0 s. At thi

tatiyna

Answer:

50 revolutions

Explanation:

Data provided:

case I: From rest to top spin

The initial angular speed of the washer, ωi = 0 rev /s

Final angular speed of the washer ωf = 5 rev /s

Time taken, t₁ = 8 s

now,

The angular displacement or the number of revolutions taken (θ₁) is calculated as:

θ₁ = ωi t₁ + (1/2)α₁t₁²

where,

α is the angular acceleration

The angular acceleration can be calculated as:

ωf - ωi = α₁t₁

on substituting the values, we get

8α₁ = 5 - 0

α₁ = 0.625 rev/s²

substituting the values in the equation for the number of revolutions, we get

θ₁ = 0 + (1/2) (0.625)(8)²

θ₁ = 20 revolutions

also,

For the case II: From top spin to rest

we have

The initial angular speed, ωi = 5 rev /s

and the final angular speed, ωf = 0 rev /s

Total time taken, t₂ = 12 s

Now, angular acceleration for this case

ωf - ωi = α₂t₂

on substituting the values, we have

12α₂ = 0 - 5

α₂ = - 0.4166 rev/s²

Therefore, the number of revolutions ( i.e angular displacement )

θ₂ = ωit₂ + (1/2)α₂t₂²

on substituting the values, we have

θ₂ = 5 × 12 + (1/2)(-0.4166)(12)²

θ₂ = 30 rev

Hence,

the total number of revolutions made by the washer during the 20s is

θ = θ₁ + θ₂

θ = 20 rev + 30 rev

θ = 50 revolutions

7 0

3 years ago

Como te llamas? (nom

lions [1.4K]

Answer: como mi llamo yo?

Explanation: in rlf Maria

4 0

3 years ago

Read 2 more answers

An echo is heard from a cliff 3.71 s after a rifle is fired. How many feet away is the cliff

LenKa [72]

The cliff is 2042 ft away.

We know that the speed of sound in air is directly proportional to the absolute temperature.

First convert the Fahrenheit temperature to Celsius;

°C = 5/9(44.5 - 32)

°C = 6.9 °C

Applying the formula;

V1/V2 = √T1/T2

Where; V1 = velocity of sound in air at 0°C

V2 = Velocity of sound in air at 6.9 °C

1087/V2 = √273/279.9

V2= 1101 ft/s

Given that; V = 2s/t

Where s is the distance of the cliff

t is the time taken

1101 ft/s = 2s/3.71 s

s = 1101 ft/s × 3.71 s/2

s = 2042 ft

Learn more:brainly.com/question/15381147

3 0

3 years ago

How can voltage be induced in a wire with the help of a magnet?

babunello [35]

If you move a magnet through a loop of wire, induction will happen. The more loops you make, the stronger the effect becomes.

3 0

3 years ago

3) A bird flies toward a tree limb at a 45-degree angle to the ground along a path that is 50 m long landing on the limb. Determ

marin [14]

Answer:

35 m

Explanation:

Given :

The distance of the path from the ground to the tree limb = 50 m

The angle between the path of flight of the bird towards the tree limb and the ground = 45 degrees

Therefore we can determine the height above which the bird perched above the ground by using the rules of the trigonometric ratios as;

We know that ,

$\sin 45^\circ =\frac{\text{perpendicular}}{\text{hypothenus}}$

$\sin 45^\circ =\frac{\text{BC}}{\text{AC}}$

$0.7 =\frac{\text{BC}}{\text{50}}$

$\text{BC }= 0.7 \times 50$

= 35

Therefore, the bird perched on the tree limb at a height of 35 m.

6 0

3 years ago