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3 years ago

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Which of these correctly describes whether a girl holding a ball in the same position is doing work on the ball?

1 answer:

aksik [14]3 years ago

4 0

Answer:

The girl is doing work on the ball because the energy in her muscles changed, even though the ball is not displaced.

Explanation:

The complete question is...

Which of these correctly describes whether a girl holding a ball in the same position is doing work on the ball?

-The girl is doing work on the ball because the energy of the ball changed, even though it is not displaced.

-The girl is doing work on the ball because the energy in her muscles changed, even though the ball is not displaced.

-The girl is doing no work on the ball because the ball is not displaced.

-The girl is doing no work on the ball because she is exerting a net force on the ball.

Holding up a ball costs energy, which is used to counter the work that would have otherwise be done on the ball by gravity. Although no physical distance is moved, we should consider the fact that by holding the ball, the girls hand exerts physical force to hold the ball in place. Also, there is a potential gravitational work on the ball due to gravity, but the force exerted by the girls hand does an equivalent of this gravito-potential work in order to counter it and hold the ball in place. All these activities eventually lead to a change in energy in her hand muscle to show that energy is expended.

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An oil tanker has collided with a smaller vessel, resulting in an oil spill in a large, calm-water bay of the ocean. You are inv

PolarNik [594]

Complete Question

An oil tanker has collided with a smaller vessel, resulting in an oil spill in a large, calm-water bay of the ocean. You are investigating the environmental effects of the accident and need to know the area of the spill. The tanker captain informs you that 18000 liters of oil have escaped and that the oil has an index of refraction of n = 1.1. The index of refraction of the ocean water is 1.33. From the deck of your ship you note that in the sunlight the oil slick appears to be blue. A spectroscope confirms that the dominant wavelength from the surface of the spill is 485 nm. Assuming a uniform thickness, what is the largest total area oil slick

Answer:

The largest total area of the oil slick $A = 8.257 *10^{9} \ m^2$

Explanation:

From the question we are told that

The volume of oil the escaped is $V = 18000 \ L$

The refractive index of oil is $n_o = 1.1$

The refractive index of water is $n_w = 1.33$

The wavelength of the light is $\lambda = 485 \ nm = 485 * 10^{-9} \ m$

Generally the thickness of the oil for condition of constructive interference between the oil and the water is mathematically represented as

$d = m *\frac{\lambda}{2n_w}$

Where is the order of interference of the light and it value ranges from 1, 2, 3,...n

It is usually take as 1 unless stated otherwise by the question

substituting value

$d = 1 * \frac{485 *10^{-9}}{2 * 1.1}$

$d = 218 nm$

The are can be mathematically evaluated as

$A = \frac{V}{d}$

Substituting values

$A = \frac{18000}{218*10^{-8}}$

$A = 8.257 *10^{9} \ m^2$

6 0

3 years ago

A pure substance can be a ..................... (a) element (b) compound (c) either element or compound (d)none of these

stiks02 [169]

Answer:

C

Explanation:

An element is a pure substance that can not be broken down into anything simpler

A compound in also a pure substance held together in fixed proportion through chemical bonds

7 0

3 years ago

Read 2 more answers

A 15-watt bulb is connected to a circuit that has a total of 60. Ω of resistance. How many electrons are passing through that bu

Mariulka [41]

Answer:

3.2075*10^16

Explanation:

Q=P/V just search up a converter and youll get 30V and so you do 15/30 which is a half and a single coulomb is 6.415*10^16 so you half it. I belive this is correct if you dont belive me wait for someone else smarter to answer and compare.

3 0

3 years ago

You can increase the vapor pressure of a liquid by:

irga5000 [103]

Answer: Option (c) is the correct answer.

Explanation:

Vapor pressure is defined as the pressure exerted by vapors or gas on the surface of a liquid.

When we increase the temperature of a liquid substance then there will occur an increase kinetic energy of the molecules. As a result, they will move readily from one place to another.

Hence, liquid state of a substance will change into vapor state of the substance. This means that an increase in temperature will lead to an increase in vapor pressure of the substance.

Thus, we can conclude that you can increase the vapor pressure of a liquid by increasing temperature.

4 0

3 years ago

What are the two kinds of nucleons?

Akimi4 [234]

Answer:

The main types of nucleons are protons and neutrons. A proton, as its name suggests, has a positive electric charge, and a neutron has a neutral electric charge (meaning that it has no charge). The two in the nucleus of the atom make a positive charge, since the neutron has no charge at all.

Explanation:

5 0

3 years ago