A 750 kg car moving at 25 m/s has Kinetic Energy. To stop the car requires work. On snowy roads, the force of friction that can
stop a car reduces to only about 725 N.
a. How much work must be done to stop the car? (Hint: What is the car's kinetic energy?)
b. How far will the car travel before stopping if the only force stopping it is friction between the tires and the road?

Answer:

To decrease the current;

1) Use fewer loops or number of turns

2) Use a lower speed of rotation of the coil in the magnetic field

3) Use a weaker magnetic

Explanation:

According to Faraday's Law of induction, which is the basis of the electromagnetism, electromagnetic induction and therefore the basis of the  electric generator, can be written as follows;

[tex]\epsilon = -N \cdot \dfrac{\Delta \phi}{\Delta t}[/tex]

Where;

ε = The induced voltage

N = The number of turns (loops)

ΔФ = The change in the magnetic flux

Δt = The change in the time (the duration)

Given that voltage is directly related to the current, decreasing the voltage, decreases the current

To decrease the voltage, and therefore, the current we can;

1) Reduce the number of loops in the coil

2) Increase the time change per unit change in flux by slowing down the speed of rotation of the generator

3) Decrease the amount of change in the magnetic field per turn, by using a weaker magnetic

Answer:

Yes, but only if it's sunny.

Explanation:

As you know, solar panels generate energy through the sun's rays of light (better known as sunlight). Therefore, as long as the sun is shining high in the sky, the car will generate electricity and be able to function. If this vehicle was only powered by solar panels, it would not function during the night, in cloudy areas, and/or in dark places (such as parking garages or home garages).

Hope this helps!

Answer:

Work is said to be done when a force applied to an object moves that object. We can calculate work by multiplying the force by the movement of the object.

Answer:

Work is done by a force on an object if (i) a force acts on the object and (ii) the object is displaced from its original position

Explanation:

that is my answer thank me later

Answer:

oxygen difluoride a polar molecule

Explanation:

Optics is a branch of physics that is the study of light and vision. ... The branch of physics dealing with the nature and properties of electromagnetic energy in the light spectrum and the phenomena of vision. In the broadest sense, optics deals with infrared light, visible light, and ultraviolet light.

Answer:

F=Gxy/r^2

Explanation:

F=Gm1m2/d^2

F=Gxy/r^2

Answer:

P = 2.33 kW

Explanation:

Given that,

Mass, m = 200 kg

It is raises in the well from a depth of 7 m in 6 s.

W e know that,

Power = work done/time

Put all the values,

[tex]P=\dfrac{mgh}{t}\\\\P=\dfrac{200\times 10\times 7}{6}\\\\P=2333.3\ W[/tex]

or

P = 2.33 kW

Hence, the power of the engine is 2.33 kW.

Explanation:

distance = velocity * time

d = 37.9 * 118

distance = 4472.2

Answer:

hi

Explanation:

Answer:

The pressure exerted by the girl is 245,000 N/m²

Explanation:

Given;

mass of the girl, m = 50 kg

area of the girl's shoe, A = 0.002 m²

The pressure exerted by the girl is calculated as follows;

[tex]P = \frac{F}{A} \\\\Where;\\F \ is \ the \ force \ exerted \ by \ girl's \ weight\\\\P = \frac{F}{A} = \frac{mg}{A} = \frac{50 \times 9.8}{0.002} = 245,000 \ N/m^2[/tex]

Therefore, the pressure exerted by the girl is 245,000 N/m²

Answer:

Explanation:

The Law of Momentum Conservation for us has the equation

[tex][m_rv_r+m_gv_g]_b=[m_rv_r+m_gv_g]_a[/tex] and filling in:

[tex][(.50)(5.0)+(.50)(0)]=[(.50)(2.0)+(.50)v_g][/tex] and

2.5 = 1.0 + .50v and

1.5 = .50v so

v = 3 m/s

The final speed of the green ball is 3m/s. This can be calculated by the law of conservation of momentum. Thus, the correct option is D.

The principle of the law of conservation of momentum states that if any two objects undergo collision, then the total momentum of the objects before and after the collision will be the same if there is no external force acting on the colliding objects.

The Law of Conservation of Momentum has the equation which is:

m₁ × u₁ + m₂ × u₂ = m₁ × v₁ + m₂ × v₂

where, m₁ = mass of object 1,

u₁ = initial velocity of object 1 before collision,

m₂ = mass of object 2,

v₁ = final velocity of object 1 after collision,

v₂ = final velocity of the object 2 after collision.

0.50 × 5 + 0.50 × 0 = 0.50 × 2 + 0.50 × v₂

2.5 + 0 = 1.0 + 0.50 × v₂

2.5 - 1.0 = 0.50 × v₂

1.5 = 0.50 × v₂

1.5/ 0.5 = v₂

v₂ = 3m/s

Therefore, the correct option is D.

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Well, let's see what we've got here:

                    ( 4⁻³ · 3⁴ · 4² )  /  ( 3⁵ · 4⁻² ) .

The two simple rules of exponents that we're

going to use here are:

-- Two multiply two numbers with the same base,

add their exponents.    Like   (A³) · (A²) = A⁵ .

But the bases have to be the same.

-- A negative power just means it belongs in the

other section of a fraction.

  A negative power on top means it belongs on the bottom.

  A negative power on the bottom means it belongs on top.

  Like    A⁻²  means  1/A² .  And  1/B⁻³  means  B³ .

That's all you need in order to clean up the big fraction

in the question.  But in order to see where you can use

these rules, you need to re-arrange things first.

Original:                          ( 4⁻³ · 3⁴ · 4² )  /  ( 3⁵ · 4⁻² )

Let's send the  4⁻³

to the bottom

where it belongs:              (   --  3⁴ · 4² )  /  4³ · ( 3⁵ · 4⁻² )

Not take that  4⁻² from

the bottom, and put it on

top, where it belongs:       (  4² · 3⁴ · 4² )  /  4³ · ( 3⁵    -- )

Multiply the 4²s on top:     (  4⁴ · 3⁴       )  /  ( 4³ · 3⁵ )

Now let me break this up.

Not changing anything, just

writing it in a different way:      ( 4⁴  /  4³ ) · ( 3⁴ / 3⁵ )

Look at the first fraction:  4⁴ / 4³ .

Divide top and bottom by  4³ , and it becomes just  4 .

Now look at the second fraction:  3⁴ / 3⁵ .

Divide top and bottom by  3⁴ , and it becomes just  1/3 .

So in the end, we're left with just      4 / 3 .

And THAT is exactly equal to the original big messy fraction

in the question.  It has exactly the same numerical value, but

you'd never know it when you see it, because it's a lot simpler.

There are a lot of other ways we could have manipulated and

massaged the original fraction, but the steps are the same:

-- Multiply numbers with the same base, by adding the exponents.

-- Remember that a number with a negative exponent belongs

in the other section of the fraction, with a positive exponent.

Answer:

a)  v₁ = - ½ v₂,  K₁ / K ₂ = ½,)

Explanation:

A) Let's use the conservation of the moment, for this we define the system formed by the spring and the two cars, so the force during the separation is internal, therefore the moment is conserved

initial instant. Before releasing the carts

         p₀ = 0

final instant. After jumping the cars

         p_f = M v₁ + m v₂₂

how the moment was preserved

        p₀ = p_f

        0 = M v₁ + m v₂

        v₁ = - m / M v₂

indicate that M = 2m

        v₁ = - ½ v₂

the kinetic energy of each car is

        K₁ = ½ M v₁²

        K₁ = ½ 2m (v₂/ 2) ²

        K₁ = m ₂v₂² / 4

        K₂ = ½ m v₂²

the relationship between the kinetic energies is

         K₁ / K₂ = ½

B) If the much greater than the mass of car 1 is mass of car 2

        v = - m / M v₂

         In this case, the speed of car 1 is very small, so the car 1 practitioner does not backtrack and car 2 leaves with a lot of speed.

The energy is still conserved, where almost all the energy has it is car 2

Answer:

Explanation:

The Law of Momentum Conservation, just like the Law of Thermodynamics about energy, says that momentum is neither created nor destroyed but is conserved, meaning it has to go somewhere. If the girl pushes the boy and they are both on friction free skates, then the girl will also react to the push. Momentum Conservation says

[tex](m_gv_g+m_bv_b)_b=(m_gv_g+m_bv_b)_a[/tex] In words this says that the mass times the velocity of the girl plus the mass times the velocity of the boy before the push has to equal the mass times velocity of the girl plus the mass times velocity of the boy after the push. Mathematically,

[tex](40.0*0+50.0*0)_b=(40.0v+50.0*-3)_a[/tex]

The left side of this is equal to 0. On the right, I made the velocity of the boy negative. We could have made it positive and it wouldn't have mattered. The sign will only be important to the result because if the sign of the girl's velocity is the same as the boy's, she is moving in the same direction as he is; if it's different, she is moving in the opposite direction.

0 = 40.0v - 150.0 and

-40.0v = -150.0 so

v = 3.75 This means that when she pushes the boy one way, mometum is conserved and she moves in the opposite direction and at a greater velocity (because her mass is less). Physics is a wonderful thing, isn't it!?

Answer:

7)  λ = 0.5 m,  8)  f = 4.8 10¹⁴ Hz

Explanation:

The speed of an electromagnetic wave is

          c = λ f

where c is the speed of light in vacuum c = 3 10⁸ m / s

7) indicate the frequency f = 6.0 10⁸ Hz

we do not know the wavelength

         λ = c / f

we calculate

        λ = 3 10⁸ / 6.0 10⁸

        λ = 0.5 m

8) indicate the wavelength  λ = 6.25 10-7 m

we do not know the frequency

         f = c / λ

we calculate

        f = 3 10⁸ / 6.25 10⁻⁷

        f = 0.48 10¹⁵ Hz

        f = 4.8 10¹⁴ Hz

Explanation:

we know that

v = m/d

or; v=1kg/800kgm^3

or; v=0. 00125m

Answer:

hey are you ok!?!?!?!

Explanation:

Is Angie your Dad new gf or wife???

Answer:

:(

Explanation:

u ok?

running away from problems only makes things worse. Your teaching urself to run. but I dont blame u

anyway hope u find what ur looking for out there!!

Answer:

1)  ΔE = -800 J, 2) ΔE = 200 J, 3)  ΔE = -200 J, 4) ΔE = 800 J

Explanation:

For this exercise let's use the first law of thermodynamics

          ΔE = Q + W

Where we will apply this expression to several cases

1) output Q = 500 J and does work of W = 300 J.

The two processes involve an energy output

         ΔE = - 500 - 300

         ΔE = -800 J

Therefore, the internal energy of the gas decreases by this amount,

2) enter Q = 500J and do work of W = 300 J

         Positive heat is added and does negative work

         ΔE = 500 - 300

         ΔE = 200 J

3) they leave Q = 500 J and do (work on the gas) W = 300J

negative heat and positive work come out

          ΔE = -500 + 300

          ΔE = -200 J

4) heat enters Q = 500 J, work on gas W = 300 J

both positive

         ΔE = 500 + 300

         ΔE = 800 J

Answer:

Final velocity = 60 m/s

Distance travelled = 9000 m

Explanation:

Applying,

For Final velocity,

v = u+at ............... Equation 1

Where v = final velocity, u = initial velocity, a = acceleration, t = time.

From the question,

Given: u = 0 m/s(at rest), a = 0.2 m/s², t = 5 minutes = (5×60) = 300 s

Substitute these values into equation 1

v = 0+0.2(300)

v = 60 m/s.

Also for distance,

Applying,

s = ut+1/2at²................ Equation 2

Where s = distance travelled.

subtitute thes values above into equation 2

s = (0×300)+(0.2×300²)/2

s = 9000 m

(a) 3.2 x 10²s

(b) 0.9 m/s (S 13 E)

(c) 2.9 x 10²m

The sketch illustrating the scenario has been attached to this response.

As shown;

The fish swims due east with a velocity [tex]V_{x}[/tex] = 0.2m/s

The river current has a velocity [tex]V_{y}[/tex] due South = 0.9m/s

The resultant of the velocity is V

The width of the river is x = 64m

(a) To calculate how long it took the fish to get across the river, we know that velocity is the rate of change in distance, therefore we can use the relation;

V = [tex]\frac{d}{t}[/tex]      -------------(i)

Where;

V = velocity of the fish = [tex]V_{x}[/tex] = 0.2m/s

d = distance from the start to the end = width of the river = x = 64m

t = time taken to move for that distance

Make t subject of the formula in equation (i);

t = [tex]\frac{d}{V}[/tex]

Substitute the values of d and V into the equation;

t = [tex]\frac{64m}{0.2m/s}[/tex]

t = 320 s

t = 3.20 x 10²s

Therefore, the time taken for the fish to get across the river is 3.20 x 10²s

(b) The resulting vector of the fish is V whose magnitude is the algebraic sum of vectors  [tex]V_{x}[/tex] and  [tex]V_{y}[/tex], and direction is given by θ. i.e

The magnitude of the resulting vector is;

|V| = [tex]\sqrt{(V_x)^2 + (V_y)^2}[/tex]

|V| = [tex]\sqrt{(0.2)^2 + (0.9)^2}[/tex]

|V| = [tex]\sqrt{(0.04) + (0.81)}[/tex]

|V| = [tex]\sqrt{(0.85)}[/tex]

|V| = 0.92m/s

|V| ≅ 0.9m/s

The direction of the resulting vector θ and is given by;

tan θ = [tex]\frac{V_y}{V_x}[/tex]

tan θ = [tex]\frac{0.9}{0.2}[/tex]

tan θ = 4.5

θ = tan⁻¹ ( 4.5)

θ = 77.47° South of East.

θ  ≈ 77.5° South of East.

Subtracting θ = 77.5° from 90° gives its value East of South

i.e

90 - 77.5 = 12.5° East of South

This can also be written as S12.5°E

Approximating to the nearest whole number gives S 13 E

Therefore, the resulting velocity of the fish is 0.9m/s in the direction S13°E

(c) When the fish arrives on the opposite bank, its distance from being at the point directly across from where it started is the product of the velocity of the river current and the time taken by the fish to get across the river. This point is equivalent to k as shown in the diagram.

Therefore;

distance = velocity of river current x time taken

distance = 0.9m/s x 3.20 x 10²s

distance = 2.88 x 10²m

distance ≅ 2.9 x 10²m

Notice that the velocity of the river current is used since that's the velocity of the fish on the y-axis.

Answer:

weight of rod =weight of liquid displaced

mass of the rod ×g =mass of liquid displaced ×g

(g cancelled out)

mass of the rod =mass of liquid displaced

density of rod ×volume of rod =density of liqiud ×volume of liquid displaced

O×cross section area of rod ×height of rod =density of liquid ×Cross section area of rod ×height of rod under the surface

O×L=density of liquid ×(L-h)

then density of liquid =OL/(L-h) shown as required

The density of the liquid is given by =OL/L − h

Density is the ratio of mass of an object and its volume.

According to the Archimedes principle, weight of rod = weight of liquid displaced

mass of the rod ×g =mass of liquid displaced ×g

So, mass of the rod =mass of liquid displaced

Mass in terms of density is substituted,

density of rod × volume of rod =density of liquid ×volume of liquid displaced

O× cross section area of rod ×height of rod =density of liquid ×Cross section area of rod ×height of rod under the surface

O×L=density of liquid ×(L-h)

Then, density of liquid =OL/(L-h).

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Answer:

Its B

Explanation:

a p e x

Answer:ur mom

Explanation:because

Answer:

(C) on edge.

Explanation:

Answer:

2.0

Explanation:

trust the process.

Answer:

the rotational kinetic energy of the disk is 5,133.375 J

Explanation:

Given;

mass of the disk, m = 27 kg

radius of the disk, r = 1.3 m

angular speed, ω = 15 rad/s

The rotational kinetic energy of the disk is calculated as;

[tex]K.E_{rot} = \frac{1}{2}I \omega^2\\\\ where;\\I \ is \ moment \ of \ inertia\\\\K.E_{rot} = \frac{1}{2} \times (mr^2) \times \omega ^2\\\\ K.E_{rot} = \frac{1}{2} \times (27\times 1.3^2) \times \ 15^2\\\\K.E_{rot} = 5,133.375 \ J[/tex]

Therefore, the rotational kinetic energy of the disk is 5,133.375 J

Answer:

Explanation:

Use the one-dimensional equation

[tex]v_f=v_0+at[/tex] where v is the final velocity, v0 is the initial velocity, a is the acceleration, and t is the time it takes to reach that final velocity. We are solving for t. Filling in the other values:

0 = 28 + (-6.4)t and

-28 = -6.4t so

t = 4.4 seconds

Answer:

4.4

Explanation:

Answer: A.

Explanation:

Máquina térmica tem como função, manter a temperatura de um dado fluído, então, a quantidade de calor desse mesmo fluído ao entrar na máquina, será igual á quantidade de calor desse fluido saindo.

Qin - Qout describes the work done by a heat engine. Hence option A is correct.

A heat engine is a system which converts heat into useful work. Carnot engine is  an ideal engine which has maximum efficiency than any other engines. Carnot has showed that "no engine can be more efficient than Carnot engine and the 100% efficient engine can not be existed". It takes heat from the reservoir to do some work and it discharges some amount of heat to the sink. Reservoir is know as hot body and sink is know as cold body.

Efficiency of the Carnot's heat engine is given by,

Efficiency, η = Work done / Heat input

Work done, W = Q1 – Q2

Heat input = Q1

Efficiency,

η = W / Q1

= (Q1 – Q2) / Q1

=1 – (Q2 / Q1).

To have engine with 100% efficiency, Q2 must be zero and it is not possible.

Hence work done by a heat engine is Qin - Qout.

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