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Sphinxa [80]
3 years ago
5

1.- An elevator is being lowered at a constant speed by a steel cable attached to an electric motor. Which statement is correct?

A. The cable does positive work on the elevator, and the elevator does positive work on the cable. B. The cable does positive work on the elevator, and the elevator does negative work on the cable. C. The cable does negative work on the elevator, and the elevator does positive work on the cable. D. The cable does negative work on the elevator, and the elevator does negative work on the cable
Physics
1 answer:
Nady [450]3 years ago
4 0

Answer:

the correct one is C

Explanation:

For this exercise we must use the work definition

    W = F. s

Where the bold characters indicate vectors and the point is the scalar producer

    W = F s cos θ

Where θ is the angles between force and displacement.

Let us support this in our case. The cable creates an upward tension and with the elevator going down the angle between them is 180º so the work of the cable on the elevator is negative.

The evade has a downward force, its weight so the force goes down and the displacement goes down, as both are in the same direction the work is positive

When examining the statements the correct one is C

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32. Which type of electromagnetic wave is used for nuclear power and medical treatment?
adelina 88 [10]

Answer:

Answers at the bottom!!

Explanation:

For the first answer: Gamma ray

Gamma rays and x-rays consist of high-energy waves that can travel great distances at the speed of light and generally have a great ability to penetrate other materials. For that reason, gamma rays (such as from cobalt-60) are often used in medical applications to treat cancer and sterilize medical instruments.

For the second answer: They both have technological uses.

In my opinion I'm pretty sure it's A because we do use microwaves and x-rays as technological uses.

Hope this helps!!

Happy Holidays and Season Greeting!!

ii Feliz Navidad a todos !!

3 0
2 years ago
Which state of matter has the greatest distance between the individual particles?
Maurinko [17]
Your answer is c steam because steam is a gas...
4 0
3 years ago
Read 2 more answers
The density of mobile electrons in copper metal is 8.4 1028 m-3. Suppose that i = 4.6 1018 electrons/s are drifting through a co
Vesna [10]

Answer:

The time is 106.7 minute.

Explanation:

Given that,

Density = 8.4\times10^{28}\ m^3

Current i = 4.6\times10^{18}\ electron/s

Diameter of wire = 1.2 mm

Length = 31 cm

We need to calculate the drift velocity

Using formula of drift velocity

v_{d}=\dfrac{I}{neA}

v_{d}=\dfrac{Ne}{tne\times\pi r^2}

Put the value into the formula

v_{d}=\dfrac{4.6\times10^{18}}{8.4\times10^{28}\times\pi\times(0.6\times10^{-3})^2}

v_{d}=4.842\times10^{-5}\ m/s

We need to calculate the time

Using formula for time

v_{d}=\dfrac{l}{t}

t=\dfrac{l}{v_{d}}

Where, l = length

v_{d} = drift velocity

Put the value into the formula

t=\dfrac{31\times10^{-2}}{4.842\times10^{-5}}

t=6402.31\ sec

t=106.7\ minute

Hence, The time is 106.7 minute.

7 0
3 years ago
Question 6
sleet_krkn [62]

Answer:

B: Process #1: Energy is decreasing Process#2: Energy is increasing

6 0
3 years ago
What impact do ocean currents have on the transfer of energy and climate
maxonik [38]

Answer:

It moderates the temperature of coastal areas. The cool waters brought into warm areas temper the climate as well as the warm waters that enter a cool area there by moderating temperatures and climates.

Explanation:

One way that the world’s ocean affects weather and climate is by playing an important role in keeping our planet warm. The majority of radiation from the sun is absorbed by the ocean, particularly in tropical waters around the equator, where the ocean acts like a massive, heat-retaining solar panel. Land areas also absorb some sunlight, and the atmosphere helps to retain heat that would otherwise quickly radiate into space after sunset.

The ocean doesn't just store solar radiation; it also helps to distribute heat around the globe. When water molecules are heated, they exchange freely with the air in a process called evaporation. Ocean water is constantly evaporating, increasing the temperature and humidity of the surrounding air to form rain and storms that are then carried by trade winds. In fact, almost all rain that falls on land starts off in the ocean. The tropics are particularly rainy because heat absorption, and thus ocean evaporation, is highest in this area.

Outside of Earth’s equatorial areas, weather patterns are driven largely by ocean currents. Currents are movements of ocean water in a continuous flow, created largely by surface winds but also partly by temperature and salinity gradients, Earth’s rotation, and tides. Major current systems typically flow clockwise in the northern hemisphere and counterclockwise in the southern hemisphere, in circular patterns that often trace the coastlines.

Ocean currents act much like a conveyor belt, transporting warm water and precipitation from the equator toward the poles and cold water from the poles back to the tropics. Thus, ocean currents regulate global climate, helping to counteract the uneven distribution of solar radiation reaching Earth’s surface. Without currents in the ocean, regional temperatures would be more extreme—super hot at the equator and frigid toward the poles—and much less of Earth’s land would be habitable.

7 0
3 years ago
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