1) what is the wavelength of your cell phone transmission?

2) How far from the building should you stand to lose reception?

3) Since the phone companies employ good engineers, that trick won't actually work. However, you happen to see a chain-link fence nearby, and (out of desperation) try to use that as a diffraction grating to scatter the radiation. Estimating the link spacing as 5 cm, will this work?

3 weeks ago

Guest #7253004

3 weeks ago

The **transmission** **waves** from a smartphone, which range in **frequency** from 800 to 2400 MHz and belong within the category of the **electromagnetic** **spectrum**, have a **wavelength** of around one foot.

**define frequency ?**

The **frequency** of a repeated event is its number of instances per unit of time. It differs from **angular** **frequency** and is sometimes referred to as temporal **frequency** for clarification. The unit of **frequency** is (Hz), or one occurrence per second. The time **lapsed** between **occurrences** is measured by the time, which is the **reciprocal** of the **frequency**.

For instance, if a ** bets **120 times per minute , the period, T—the space between bets—is half a second. The **frequency** of oscillatory and **vibrtory** **phenomena**, such as **mechanical vibrions**, sound, and **radio waves**, is a crucial characteristic in science and **engineering**.

The **transmission** **waves** from a smartphone, which range in **frequency** from 800 to 2400 MHz and belong within the RF category of the **electromagnetic** **spectrum**, have a **wavelength** of around one feet.

Standing **8 feet **away is advised, according to **FEMA**.

To learn more about **frequency** follow the given link: https://brainly.com/question/26754018

#SPJ4

Question

A bus slows down from 8.22 m/s to a stop in 13.3 s. Its wheels have a radius of 0.530 m. Find the initial angular speed of the wheels.

Solution 1

**Answer:**

**The initial angular velocity of the bus wheel:**

**ω₀ ≈ 15.6 rad / s**

**Explanation:**

Given:

V₀ = 8.22 m/s - **Starting speed of the bus**

V= 0 m/s - **Final speed of the bus (the bus has stopped)**

ω = 0 rad/c - **Final angular velocity of the bus wheel**

t = 13.3 s - **Bus deceleration time**

R = 0.530 m - **Bus wheel radius**

____________________

ω₀ - ? - **The initial angular speed of the wheels.**

1)** Bus linear acceleration module:**

a = ( V₀ - V) / t = (8.22 - 0) / 13.3 ≈ 0.62 m/s²

2) **Bus angular accelerations module:**

ε = a / R = 0.62 / 0.530 ≈ 1.17 rad / s²

3) **The initial angular velocity of the bus wheel:**

ω₀ = ε·t = 1.17·13.3 ≈ **15.6 rad / s**

Question

A sound pulse emitted underwater reflects off a school of fish and is detected at the same place 0.10 s later. How far away are the fish? (Assume the water temperature is 20 degrees C.)

Solution 1

I'll assume that the **properties** of the water are that sound waves in fresh water move at a speed of 1497 m/s at a temperature of 25 °C. If the speed is 0.01s, you must divide it by 100 to get 14.97; but, since it travels there and back in 0.01s, you must split it in half i.e 7.485m.

**Without a medium, what kind of wave can travel?**

**Electromagnetic** waves

In contrast to mechanical waves, electromagnetic waves can travel without a medium. This implies that electromagnetic waves can pass not only through solid objects like air and rock but also through empty space.

Answer and **justification** Since electromagnetic waves are not conveyed by the vibration of particles, they do not need a medium to travel. Electric and magnetic fields, which can exist anywhere, oscillate, creating waves. Waves can therefore exist in solids, liquids, gases, or empty space.

Know more about **reflection**:

brainly.com/question/26494295

#SPJ1

Question

Which of the position versus time graphs below matches the following description: a speed versus time graph has a horizontal line at 5 m/s from zero to five seconds?

Solution 1

The **position versus time graph** that matches the description: a **speed** versus time graph has a horizontal line at 5 m/s from zero to five seconds is Graph A; The correct option is A.

A **position versus time graph **is a graph that plots the position of an object against the time it takes for the object to move from one point to another.

The slope of a position versus time graph represents the **speed** or velocity of the object.

The slope of a position time graph = distance or position/time

A speed versus time graph is a graph that plots the speed of an object against the time it takes for the object to move to that speed.

The slope of a position versus time graph represents the **acceleration** of the object.

Considering the given **speed versus time graphs**:

Graph A: the speed versus time graph has a horizontal line at 5 m/s from zero to five seconds.

Graph B: the speed versus time graph shows variation is speed over time

Graph C: the speed versus time graph shows a constant increase in speed over time

Graph D; the speed versus time graph shows a constant decrease in speed over time

Learn more about **speed versus time graph **at: https://brainly.com/question/13879554

#SPJ1

Question

6. Mikey can kick the ball to Sage with a force of 20 N, making it travel 60m. Give the work done on the ball.

Solution 1

**Answer:**

**Explanation:**

Given:

F =20 N

D = 60 m

________

W - ?

W = F·D = 20·60 = 1 200 J

Question

.

A 2155 kg demolition ball swings at the end of a 17.5m cable on the arc of a vertical

circle. At the lowest point of the swing, the ball is moving at 8.6m/s. Determine the

tension in the cable at the lowest point. (Hint: T-mg =mv^2/r)

Solution 1

**Answer:**

**Thread tension:**

**T =** F + P = 9 108 + 21 120 ≈ **30 230 N**

**Explanation:**

Given:

m = 2155 kg

R = 17.5 m

V = 8.6 m/s

g = 9.8 m/s²

_______________

T - ?

**Modulus of centripetal force (force is directed towards the center of the circular arc):**

[tex]F = \frac{m\cdot V^2}{R} = \frac{2155\cdot 8.6^2}{17.5} = 9108 N[/tex]

**Ball weight (directed vertically down):**

*W = m·g = 2155·9.8 ≈ 21 120 N*

**Let's use the hint. Thread tension:**

**T =** F + W = 9 108 + 21 120 ≈ **30 230 N**

Solution 2

The **tension** in the cable at the lowest point of the swing is [tex]30248.196 N[/tex].

To determine the **tension **in the cable at the lowest point of the** swing**, we can use the hint provided:

[tex]T-mg=\frac{mv^{2}}{r}[/tex]

where T represents** tension**,

m is the mass of the **demolition ball** (2155 kg),

g is the **acceleration** due to gravity (approximately 9.8 m/s^2),

v is the **velocity** of the ball (8.6 m/s), and

r is the** radius** of the circular path (17.5 m).

Plugging in the given values, we have:

[tex]T-2155\times 9.81=\frac{2155\times 8.6^{2}}{17.5}[/tex]

[tex]T=30248.196 N[/tex]

Therefore, the **tension** in the cable at the lowest point of the** swing** is approximately [tex]30248.196 N[/tex].

Learn more about **tension** here:

https://brainly.com/question/29763438

#SPJ2

Question

Baseballs aren’t especially bouncy. A baseball fired at 20 m/s

at a solid wall rebounds at 11 m/s. What fraction of the initial kinetic energy is transformed into thermal energy?

at a solid wall rebounds at 11 m/s. What fraction of the initial kinetic energy is transformed into thermal energy?

Solution 1

The fraction of the **initial kinetic energy **is transformed into **thermal energy **is 3/4.

The fraction of the** initial kinetic energy** is transformed into **thermal energy **is calculated by applying the principle of conservation of energy as shown below.

Mathematically, this is given as;

ΔK.E = E

where;

- ΔK.E is the change in kinetic energy
- E is the thermal energy

E = K.Ef - K.Ei

where;

- K.Ef is the final kinetic energy
- K.Ei is the initial kinetic energy

E = (¹/₂mu² - ¹/₂mv²) / (¹/₂mu²)

where;

- m is the mass of the baseball
- v is the final velocity of the baseball
- u is the initial velocity of the baseball

E = (u² - v²) / (u²)

E = (20² - 10²) / (20²)

E = 0.75 = 3/4

Thus, the fraction of the **initial kinetic energy **is transformed into **thermal energy **is a function of the change in speed of the baseball.

Learn more about **kinetic energy** here: https://brainly.com/question/25959744

#SPJ1

Question

Polaris is also called the North Star because Earth's North

Pole points toward it. As Earth rotates, other stars seem to

spin around Polaris in a counterclockwise direction. In one.

day, the stars will make one complete circle (360°) around

Polaris. Compare the positions of the constellations in the

two diagrams. Calculate how many hours have passed

between the first and second diagrams.

Pole points toward it. As Earth rotates, other stars seem to

spin around Polaris in a counterclockwise direction. In one.

day, the stars will make one complete circle (360°) around

Polaris. Compare the positions of the constellations in the

two diagrams. Calculate how many hours have passed

between the first and second diagrams.

Solution 1

**Answer:****.****.****.****.****.****.****.****.****.****.****.****.****.****.****.****.**

**Explanation:****.****.****.****.****.****.****.****.****.****.****.****.****.**

Question

what is the acceleration of a 38 kg crate being pushed horizontally by an 83 N force?

Solution 1

The magnitude of **acceleration **of the crate be **7.14 m/s².**

**Acceleration **is rate of change of velocity with time. Due to having both direction and magnitude, it is a vector quantity. Si unit of **acceleration **is meter/second² (m/s²).

**Mass **of the create be: m = 38kg.

**Force **applied on the create : F = 83N.

From Newton's** second law of motion**, we can write:

**force **= mass × acceleration

⇒ **acceleration **= force/mass = 38/83m/s² = 0.45 m/s².

Hence, **acceleration **of the create be 0.45 m/s².

Learn more about **acceleration **here:

brainly.com/question/12550364

#SPJ1

Question

Using the right hand rule, what do the three numbered vectors represent in the diagram below?

Solution 1

Using the right-hand rule, the correct answer is:

A) Magnetic field

B) Electric current

C) Force

The equation corresponding to this graphical representation is

F = IBL

where I is the current, B the magnetic field, L the length of the wire and F the magnetic force.

A) Magnetic field

B) Electric current

C) Force

The equation corresponding to this graphical representation is

F = IBL

where I is the current, B the magnetic field, L the length of the wire and F the magnetic force.

Question

You measure the period of a pendulum and get 25s. What is the length of the pendulum?

Solution 1

**Answer:**

**Explanation:**

T = 25 s

25 = 2*pi*sqrt(L/9.8)

L = 155.14 m

Mathematics
2410639

English
568681

History
480985

Biology
357176

Chemistry
274132

Social Studies
272936

Business
249918

Physics
216424

Health
119193

Spanish
99545

Computers and Technology
80770

Geography
70262

Arts
65481

Medicine
36431

Law
25365

SAT
24518

French
20622

Engineering
19413

World Languages
18387

Advanced Placement (AP)
18095

German
3100

High School
3201891

College
1926950

Middle School
303232