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Digiron [165]
2 years ago
6

Plsss help I don’t understand this

Physics
2 answers:
nekit [7.7K]2 years ago
6 0

B is the correct option.

1. Given eqn;

S(t) = 1/2t² - 4t + 8

2.Differentiate the above eqn with respect to t;

<u>d(S(t))</u> = t - 4

dt

When distance, S, is differentiated it results to velocity.

V = t - 4

at t = 10

V = 10 - 4

V = 6 feet/s

mixer [17]2 years ago
4 0
The person above is correct, it’s B
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Particle A of charge 2.79 10-4 C is at the origin, particle B of charge -5.64 10-4 C is at (4.00 m, 0), and particle C of charge
kirill [66]

Answer:

a) 0 b) 29.9 N c) 21.7 N d) -17.4 N e) -13.0 N f) -17.4 N  g) 16.9 N

h) 24.3 N θ = 44.2º

Explanation:

a) As the electric force is exerted along the line that joins the charges, due to any of the charges A or C has non-zero x-coordinates, the force has no x components either.

So, Fcax = 0

b) Similarly, as Fx = 0, the entire force is directed along the y-axis, and is going upward, due both charges repel each other.

Fyca = k*qa*qc / rac² = (9.10⁹ N*m²/C²*(2.79)*(1.07)*10⁻⁸ C²) / 9.00 m²

Fyca = 29. 9 N

c) In order to get the magnitude of the force exerted by B on C, we need to know first the distance between both charges:

rbc² = (3.00 m)² + (4.00m)² = 25.0 m²

⇒ Fbc = k*qb*qc / rbc² = (9.10⁹ N*m²/C²*(5.64)*(1.07)*10⁻⁸ C²) / 25.0 m²

⇒ Fbc = 21.7 N

d) In order to get the x component of Fbc, we need to get the projection of Fcb over the x axis, taking into account that the force on particle C is attractive, as follows:

Fbcₓ = Fbc * cos (-θ) where θ, is the angle that makes the line of action of the force, with the x-axis, so we can write:

cos θ = x/r = 4.00 / 5.00 m =

Fcbx = 21.7*(-0.8) = -17.4 N

e) The  y component can be calculated in the same way, projecting the force over the y-axis, as follows:

Fcby = Fcb* sin (-θ) = 21.7* (-3.00/5.00) = -13.0 N

f) The sum of both x components gives :

Fcx = 0 + (-17.4 N) = -17.4 N

g) The sum of both y components gives :

Fcy = 29.9 N + (-13.0 N) = 16.9 N

h) The magnitude of the resultant electric force acting on C, can be found just applying Pythagorean Theorem, as follows:

Fc = √(Fcx)²+(Fcy)² = (17.4)² + (16.9)²\sqrt{((17.4)^{2} +(16.9)^{2}} = 24.3 N

The angle from the horizontal can be found as follows:

Ф = arc tg (16.9 / 17.4) = 44.2º

4 0
3 years ago
Which explanations provide support for continental drift theory? Check all that apply.
denis23 [38]
<h3><u>Full Question:</u></h3>

Which explanations provide support for continental drift theory? Check all that apply.

Dinosaurs lived on many continents.

Coal fields match up across continents.

Tropical plant fossils were found in Arctic areas.

Similar rock types are found across continents.

Evidence of glaciers can be found in South Africa.

Coal fields match up across continents.

Similar rock types are found across continents.

Tropical plant fossils were found in Arctic areas.

Evidence of glaciers can be found in South Africa.

<h3><u>Explanation:</u></h3>

The way the continents on the earth shifts its position is explained by the Continental drift theory. Alfred Wegener was the one who fist proposed this theory in 1912. This theory also explains how similar rocks are formed on the different continents and also  the reason why some of the animal and plant fossils looks similar.

The evidences that supports the continental drift theory can be Coal fields match up across continents. Fossils of Glossopteris supports the  theory of continental drift with coal fields  and coastlines . The land features, climate changes are some of the evidences that also supports the theory of continental drift.The evidences of the glaciers that can be found in South Africa also supports the explanation of the continental drift.

8 0
3 years ago
If you are given force and time, you can determine power if you can know watts energy joules distance
shepuryov [24]

Answer:

distance

Explanation:

Distance is the missing quantity. It is needed to estimate the amount of work done by a force, and afterwards it is used to estimate the power, which is the work done over the time it took to complete it.

8 0
3 years ago
Read 2 more answers
Andre is studying snails and how fast they travel. He observes three groups of snails containing four snails each. Here are the
Olin [163]
The material that the snails are moving on affects their speed. On a smooth material, (petri dish) the snails moved the fastest. On a rough material (sandpaper) the snails moved the slowest. On dirt, a compromise between smooth and rough, the snails moved at a medium pace. The material and possibly friction affect this.
4 0
3 years ago
Which of the following statements are true? Check all that apply.
lidiya [134]

We have 6 levels and we will verify which of them is true.

<em>A ) Electric charge is conserved </em>

According to the conservation of charge, an electric charge can neither be created nor be destroyed.

Therefore this statement is TRUE.

<em>B ) A positive charge and negative charge attract each other</em>

According to the properties of charges, the opposite charges attract each other and similar charges repel each other

Therefore this statement is  TRUE

<em>C) Two positive charges attract each other.</em>

Using the previous law, we can observe that this statement is false, because equal charges repel each other.

Therefore this statement is FALSE.

<em>D ) Two negative charges repel each other.</em>

Using the same principle as the two previous statements, two equal charges repel each other.

Therefore this statement is TRUE

<em>E) Electric charge is quantized.</em>

According to the quantization of charge, charges can take values only in integral multiples of a fundamental unit of charge.

Therefore this statement is TRUE.

<em>F) A neutral object contains no charge.</em>

A neutral object contains equal amount of negative and positive charge. Thus, in totality a neutral object contains no charge.

Therefore this statement is TRUE.

8 0
3 years ago
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