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2 years ago

a 10-N force is exerted on a box, moving it 20 m in the same direction. What is the magnitude of work done on the box?

1 answer:

8 0

F = 10 N

d = 20 m

θ = 0°

W = F (dot product) D = F * D * cos(angle between them)

W = FDcosθ

W = 10 * 20 * cos0 = 200 J

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3 years ago

A solid, cylindrical wire conductor has radius R = 30 cm. The wire carries a current of 2.0 A which is uniformly distributed ove

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Answer:

Explanation:

The point at which magnetic field is to be found lies outside wire so while applying Ampere's law we shall take the whole of current . If B be magnetic field which is circular around conductor.

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3 years ago

In which one(s) of the following situations will there be an INCREASE in Kinetic Energy? Group of answer choices A block slides

Maksim231197 [3]

Answer:

The Kinetic Energy INCREASE in the following situations:

a)A block slides down a frictionless incline:

e)A merry go round rotates faster due to the push by a person.

Explanation:

The energy kinetics is proportional to the square of the velocity:

$E_k=1/2*mv^2$

We study the cases:

a)A block slides down a frictionless incline:

The gravity made a positive work and the box get a extra velocity, then the kinetics energy INCREASE

b)A box is pulled across a rough floor at constant speed:

The magnitude of the velocity does not change, so the kinetics energy does not change as well

c)A stone at the end of a string is whirled in a horizontal circle at constant speed:

The magnitude of the velocity does not change, so the kinetics energy does not change as well

d)A projectile approaches its maximum height:

If the projectile approaches its maximum height, its velocity approaches to zero. Then the kinetics Energy DECREASE

e)A merry go round rotates faster due to the push by a person.

Thanks to the push, the magnitude of the velocity INCREASE, so the kinetics energy INCREASE as well

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3 years ago

What happens to the density of a fluid as the substance gains thernal energy

Natalka [10]

Density reduces

Explanation:

The density of a fluid will reduce as a substance gains more thermal energy. Heat is a form of thermal energy usually noticed as temperature differences in a matter.

When thermal energy is gained by a body, the temperature of the body rises.
The particles of the medium gains more kinetic energy.
This causes the substance to expand and it has more volume.
When a substance expands, it occupies more space.
The more the volume a body occupies, the lesser the density.
Expansion does not change the mass of the fluid but the volume changes.
This is why density decreases.

Learn more:

Density brainly.com/question/8441651

#learnwithBrainly

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3 years ago

A type of Lead (Pb) ion has a + 4 oxidation number. Sulfur (S) has a — 2 oxidation number. What would be the chemical formula fo

serious [3.7K]

Answer: The chemical formula for the compound of these two elements is $PbS_2$

Explanation:

For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.

Here metal lead is having an oxidation state of +4 called as $Pb^{4+}$ cation and sulphur non metal has oxidation state of -2 called as $S^{2-}$ . Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral $PbS_2$

The chemical formula for the compound of these two elements is $PbS_2$

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3 years ago