PLEASE HELP!!!!
A person pushes attempts to push a couch with a 25 N force. The couch, however, doesn't move. What is the static friction force acting on the couch? *
A. 25 N
B. 0 N
C. 50 N
D. There is no static friction the ONLY force acting on the couch is the push

(a) 4.20 J

(b) 16.74 J

For a parallel plate vacuum capacitor with area A and whose plates are separated by by a distance of d, its capacitance C is given by;

C = A∈₀ / d              --------------------(i)

Where;

∈₀ = constant called permittivity of vacuum.

The energy U stored in such capacitor is given by;

U = [tex]\frac{1}{2}[/tex]CV²             ----------------------(ii)

or

U =  [tex]\frac{1}{2}[/tex](Q²/C)        -------------------(**)

Where;

V = potential difference or voltage across the plates.

Q = charge on the plates.

(a) If the charge is held constant

Combine equations (i) and (**) to give;

U =  [tex]\frac{1}{2}[/tex]Q² / (A∈₀ / d)     -----------------------(iii)

From the question;

The parallel plate capacitor has 8.40J energy stored and distance between plates is 2.30mm i.e

U = 8.40J

d = 2.30mm = 0.023m

Substitute these values into equation (iii)

8.40 =  [tex]\frac{1}{2}[/tex]Q² / (A∈₀ / 0.023)

8.40 =  [tex]\frac{1}{2}[/tex]Q² x (0.023 / A∈₀)

Multiply through by 2

2 x 8.40 = Q² x (0.023 / A∈₀)

16.80 = Q² x (0.023 / A∈₀)

Divide through by 0.023

16.80 / 0.023 = Q² x (0.023 / A∈₀) / 0.023

730.4 = Q² / (A∈₀)

Make Q² subject of the formula

Q² = 730.4(A∈₀)

Now, if the separation distance is decreased to 1.15mm and the voltage is held constant i.e

d = 1.15mm = 0.0115m

Q = constant [this means that Q² still remains 730.4(A∈₀) ]

The energy stored is found by substituting these values of d and Q² into equation (iii) as follows;

U =   [tex]\frac{1}{2}[/tex]Q² / (A∈₀ / d)

U = [tex]\frac{1}{2}[/tex](730.4(A∈₀)) / (A∈₀ / 0.0115)

U = [tex]\frac{1}{2}[/tex](730.4(A∈₀))(0.0115 / A∈₀)

U = [tex]\frac{1}{2}[/tex](730.4)(0.0115)

U = 4.20J

Therefore, the energy stored if the charge Q on the plates is held constant is 4.20 J

(b) If the voltage is held constant

Combine equations (i) and (ii) to give;

U =  [tex]\frac{1}{2}[/tex](A∈₀ / d)V²     -----------------------(iv)

From the question;

The parallel plate capacitor has 8.40J energy stored and distance between plates is 2.30mm i.e

U = 8.40J

d = 2.30mm = 0.023m

Substitute these values into equation (iv)

8.40 =  [tex]\frac{1}{2}[/tex](A∈₀ / 0.023)V²

Multiply through by 2 x 0.023

2 x 0.023 x 8.40 = (A∈₀)V²

2 x 0.023 x 8.40 = (A∈₀)V²

0.385 = (A∈₀)V²

Make V² subject of the formula

V² = 0.385/(A∈₀)

Now, if the separation distance is decreased to 1.15mm and the voltage is held constant i.e

d = 1.15mm = 0.0115m

V = constant [this means that V² still remains 0.385/(A∈₀) ]

The energy stored is found by substituting these values of d and V² into equation (iv) as follows;

U =  [tex]\frac{1}{2}[/tex](A∈₀ / 0.0115)[0.385/(A∈₀)]  

U = [tex]\frac{1}{2}[/tex](0.385/0.0115)

U = 16.74

Therefore, the energy stored if the voltage V across the plates is held constant is 16.74 J

Answer:

the energy possessed by a body by virtue of its position relative to others, stresses within itself, electric charge, and other factors.

hope this helps

have a good day :)

Explanation:

Answer:

Potential Energy is the stored energy in an object or system because of its position or configuration.

Explanation:

Example: Water at the top of a waterfall, before the precipice.

Answer:

Explanation:

The angular momentum of that same disk-sphere remains unchanged the very same way before and after the impact of the collision when the clay sphere adheres to the disk.

 [tex]\mathbf{I_w}[/tex] = constant.

The overall value of such moment of inertia is now altered when the clay spherical sticks. Due to the inclusion of the clay sphere, the moment of inertia will essentially rise. As a result of this increase, the angular speed w decreases in value.

Recall that:

The Kinetic energy is given by:

[tex]\mathbf{K = \dfrac{1}{2} Iw^2} \\ \\\mathbf{K = \dfrac{1}{2} lw*w}[/tex]

where;

[tex]\mathbf{I_w}[/tex] is constant and w reduces;

As a result, just after the collision, the system's total kinetic energy decreases.

The total kinetic energy of the system decreases after the collision.

The angular momentum of any rotating body is defined as the product of the moment of inertia of the body and the angular velocity of the body.

Now from the question, we can see that the angular momentum of the body remains constant before and after the impact of the collision when the clay sphere adheres to the disk.

So angular momentum will be

[tex]Iw[/tex] = constant.

The overall value of such a moment of inertia is now changed when the clay spherical sticks. Due to the inclusion of the clay sphere, the moment of inertia will essentially rise. As a result of this increase, the angular speed w decreases in value.

The Kinetic energy is given by:

[tex]KE=\dfrac{1}{2} Iw^2[/tex]

[tex]KE= \dfrac{1}{2} Iw\times w[/tex]

Since the angular momentum [tex]Iw[/tex] is constant and w is reducing then ultimately the energy of the system is decreasing.

Thus the total kinetic energy of the system decreases after the collision.

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Answer:

This is because the age of the universe is determined by the pace of expansion in the past, and each model forecasts a different pace.

Explanation:

The age of the universe is determined by the pace of expansion in the past, and each model forecasts a different pace.

This is due to the fact that the expansion rate in the coasting model is constant and never changes. Because the cosmos is growing faster now than during the old days, recollapsing and critical models give shorter ages. According to the accelerating model, the universe is growing at a slower rate currently than in the past, implying an older age.

Speed = distance / time

Speed = 120 km / 2 1/2 hours

Speed = 48 km per hour

If two objects are the SAME temperature and are physically touching,

then

. . .

. . .

. . .

The objects would be in thermodynamic equilibrium and as a result there would be no heat transfer.

Answer:

1. 0.57 m/s

2. 25 Watts

Explanation:

1. Determination of the speed.

We'll begin by converting 1.5 hp to watt (W). This can be obtained as follow:

1 hp = 745.7 W

Therefore,

1.5 hp = 1.5 hp × 745.7 W / 1 hp

1.5 hp = 1118.55 W

Next, we shall determine the force. This can be obtained as follow:

Mass (m) = 200 Kg

Acceleration due to gravity (g) = 9.8 m/s²

Force (F) =?

F = m × g

F = 200 × 9.8

F = 1960 N

Finally, we shall determine the speed. This can be obtained as follow:

Power (P) = 1118.55 W

Force (F) = 1960 N

Speed (v) =?

P = F × v

1118.55 = 1960 × v

Divide both side by 1960

v = 1118.55 / 1960

v = 0.57 m/s

Thus, the speed is 0.57 m/s

2. Determination of the power.

We'll begin by calculating the velocity. This can be obtained as follow:

Displacement = 10 m up

Time = 20 s

Velocity =?

Velocity = Displacement / time

Velocity = 10 / 20

Velocity = 0.5 m/s

Finally, we shall determine the power. This can be obtained as follow:

Velocity (v) = 0.5 m/s

Force (F) = 50 N

Power (P) =?

P = F × v

P = 50 × 0.5

P = 25 Watts

Therefore, the power required to lift the bucket is 25 Watts

Answer:

the answer should be D

Explanation:

Because if you want to earn your goals you must complete small goals to earn big goals

Answer:

Impulse = Average force x time of contact

Explanation:

Impulsive force is a force which is very large but applied on a body for a very small duration of time.

Impulse is given by the change in momentum of the body.

Impulse = Average force x small time interval

When padding is there, the time interval of contact is large and thus, the force exerted by the body is small.

So, when a person falls on the tile floor, there is no compression and thus, the time of contact is very small and thus the impulsive force is very large, due to  which the body may damage.

So, when a person falls on the carpeted floor, there is a compression and thus, the time of contact is comparatively large and thus the impulsive force is small, due to  which the body may safe.

Explanation:

Answer:

y = y₀ / 4

Explanation:

In a double slit experiment the constructive interference lines are given by

          d sin θ = m λ

if we use trigonometry

          tan θ = y / L

as in these experiments the angles are very small

          tan θ = sin θ /cos θ = sin θ

we substitute

         sin θ = y / L

          d y / L = m λ

let's use a subscript "o" for the initial values  

          I = m λ₀ L /d₀

They ask us to decrease the wavelength by 2

           λ =  λ₀ / 2

the distance in the slit is increased by a factor of two

         d = 2 d₀

we substitute

          2d₀  y/L = m  λ₀/2

          y = m  λ₀ L/d₀    ¼

          y = y₀ / 4

Answer:

C

Explanation:

correct me if I'm wrong.

Answer:

A

Explanation:

i got it right on acellus

a = (dx / dt)²

Explanation:  Unit of distance is m (metres) and unit of time is s (seconds) speed v is  first derivative of distance x versus time:

  v = dx / dt, unit is m/s.    Acceleration is second derivative of

 speed versus time  a = (dx / dt)² = (dv/dt) , unit is m/s²

Answer:

Explanation:

Acceleration is derived unit because it has two fundamental units involved i.e. meter and second square.

Answer:

The spring constant is 173.12 N/m.

Explanation:

mass, m = 32 kg

Period, T = 2.7 s

let the spring constant is K.

Use the formula of period,

[tex]T = 2\pi\times \sqrt \frac{m}{K}\\\\2.7 =2\times 3.14\sqrt\frac{32}{K}\\\\K = 173.12 N/m[/tex]

Explanation:

A socio-economically disadvantaged child is the one who is disadvantaged in terms of social position and economic position. Such children have limited resources in terms of education, money and future options. Four ways of helping such children are as follows:

1) Help them in education - You can help such children by giving them free tuition. If you belong to a well off family, you can get them admitted in schools as well. Provide them with books and uniform.

2) Encourage them to do well in school and pursue their passions.

3) Provide them with meals, if they do not have access to regular meals.

4) encourage them to go school regularly.

Answer:

Answer:

a. True

Explanation:

Conduction involves the transfer of electric charge or thermal energy due to the movement of particles. When the conduction relates to electric charge, it is known as electrical conduction while when it relates to thermal energy, it is known as heat conduction.

A conductor can be defined as any material or physical object that allows the conduction (transfer) of electric charge or thermal energy. Some examples of conductors are metal, steel, aluminum, copper, frying pan, pot, metallic spoon, etc.

During heat conduction, thermal energy is usually transferred from fast moving particles to slow moving particles during the collision of these particles.

Furthermore, any charge that is added to a conductor would quickly spread over the surface of the conducting object due to the fact that it allows the movement of subatomic particles.

Answer: True

Explanation: Aced Test

Answer:

s = 11250 m = 11.25 km

Explanation:

The distance covered by the sound wave while traveling from submarine to ocean floor and then back to submarine can be given as follows:

[tex]s = vt[/tex]

but, the distance between the floor and the submarine will be half of this value:

[tex]s = \frac{1}{2}vt[/tex]

where,

s = distance between submarine and ocean floor = ?

v = velocity of sound = 1500 m/s

t = time taken for the round trip = 15 s

Therefore,

[tex]s = \frac{1}{2}(1500\ m/s)(15\ s)[/tex]

s = 11250 m = 11.25 km

Answer:

A

Explanation:

Answer:

Option 2

Explanation:

The complete question is

A 50 kg child sits on the left side of the bathtub. A small toy boat of 0.5 kg is on the right side of the bathtub. Which part of the bathtub has the greatest pressure

Solution

It is the bottom of the bucket that will high pressure because of the additional weight of 50 Kg boy along with the weight of the water and the tub itself.

Pressure acts in the down ward direction and is equal to the force/weight divided by the area.

Hence, option 2 is correct

Answer:

52.5 J

Explanation:

Applying,

Hook's law,

F = ke............... Equation 1

Where F = Force, k = spring constant, e = extension.

make k the subject of the equation

k = F/e............ Equation 2

From the question,

Given: F = 350 Newtons, e = 30 cm = 0.3 m

Substitute these values into equation 2

k = 350/0.3 N/m

Also,

W = 1/2(ke²).................. Equation 3

Where W = work done in stretching the spring.

Also given: e = (50-20) cm = 30 cm = 0.3 m, k = 350/0.3 N/m

Substitute these values into equation 3

W = 1/2(350/0.3)(0.3²)

W = 350×0.3/2

W = 52.5 J

Answer:yeah it A

Explanation:

Answer:

the correct answer is c

Explanation:

In this exercise we seek the momentum

          I = F t

this value is set because forces and time are given.

Now we can use the relationship between linear momentum and momentum

         I = p_f - p₀

         I = m v_f - m v₀

suppose that the two spheres depart with the same initial velocity

Let's analyze these results, the value of the impulse is the same, so the body of lower mass must acquire greater speed or momentum

consequently the lighter sphere acquires more final speed, but the change of momentum is the same in the two spheres

Consequently the correct answer is c

Answer:

0.9378

Explanation:

Weight (W) of the rider = 100 kg;

since 1 kg = 9.8067 N

100 kg will be = 980.67 N

W = 980.67 N

At the slope of 12%, the angle θ is calculated as:

[tex]tan \ \theta = \dfrac{12}{100} \\ \\ tan \ \theta = 0.12 \\ \\ \theta = tan^{-1}(0.12) \\\\ \theta = 6.84^0[/tex]

The drag force D = Wsinθ

[tex]\dfrac{1}{2}C_v \rho AV^2 = W sin \theta[/tex]

where;

[tex]\rho = 1.23 \ kg/m^3[/tex]

A = 0.9 m²

V = 15 m/s

∴

Drag coefficient [tex]C_D = \dfrac{2 *W*sin \theta}{\rho *A *V^2}[/tex]

[tex]C_D =\dfrac{2 *980.67*sin 6.84}{1.23 *0.9 *15^2}[/tex]

[tex]C_D =0.9378[/tex]

Answer:

to be honest i dont know

Explanation:

^^

(a) 42m/s

(b) 15m/s

Given:

The position of a particle at time t

s(t) = t³ + 3t

(i) To compute the average velocity

Average velocity ([tex]V_{avg}[/tex]) is given by the quotient of the change in position and change in time at a given interval of time. i.e

[tex]V_{avg}[/tex] = Δs / Δt

[tex]V_{avg}[/tex] = (s₂ - s₁) / (t₂ - t₁)             --------------------(ii)

Given interval of time is [2,5]

Therefore,

t₁ = 2

t₂ = 5

s₁ = position of the particle at t₁.

This is found by substituting t = 2 into equation (i)

s₁ = (2)³ + 3(2)

s₁ = 8 + 6 = 14

s₂ = position of the particle at t₂

This is found by substituting t = 5 into equation (i)

s₂ = (5)³ + 3(5)

s₂ = 125 + 15 = 140

Now, substitute t₁, t₂, s₁ and s₂ into equation (ii) as follows;

[tex]V_{avg}[/tex] = (s₂ - s₁) / (t₂ - t₁)

[tex]V_{avg}[/tex] = (140 - 14) / (5 - 2)

[tex]V_{avg}[/tex] = 126 / 3

[tex]V_{avg}[/tex] = 42

Therefore, the average velocity is 42m/s

(ii) To compute the instantaneous velocity.

The instantaneous velocity is the velocity of the particle at a given instant in time.

The given instant in time is t = 2.

To get the instantaneous velocity (V), differentiate equation (i) with respect to t as follows;

V = [tex]\frac{ds}{dt}[/tex]

V = [tex]\frac{d(t^3 + 3t)}{dt}[/tex]

V = 3t² + 3

Now substitute the value of t = 2 into the above equation

V = 3(2)² + 3

V = 12 + 3

V = 15

Therefore, the instantaneous velocity at t = 2 is 15m/s

Answer:

W = 3/2 n (T₁- T₂)

Explanation:

Let's use the first law of thermodynamics

           ΔE = Q + W

in this case the cylinder is insulated, so there is no heat transfer

           ΔE = W

internal energy can be related to the change in temperature

            ΔE = 3/2 n K ΔT

we substitute

           3/2 n (T₂-T₁) = W

as the work is on the gas it is negative

            W = 3/2 n (T₁- T₂)

Answer:

[tex]I=11.1A[/tex]

Explanation:

From the question we are told that:

Radius [tex]R=2.80[/tex]

Turns [tex]N=790[/tex]

Magnetic field B=0.0760

Generally the equation for Magnetic field at the center of the coil is mathematically given by

 [tex]B=\frac{\mu NI}{2r}[/tex]

 [tex]0.076=\frac{4\p*10^-^7*790*I}{2*0.028}[/tex]

 [tex]I=\frac{0.076*2*0.028}{4\p*10^{-7}*790}[/tex]

 [tex]I=11.1A[/tex]

Answer:

B on edge2020-2021

Explanation:

Answer:

(a) Negative Q

(b) Positive Q

Explanation:

Charge is the inherent property of matter due to the transference of electrons.

There are three methods of charging a body.

(i) Charging by friction: When two uncharged bodies rubbed together, then one body gets positive charged and the other is negatively charges it is due to the transference of electrons form one body to another.  

(ii) Conduction: when a charged body comes in contact with the another uncharged body, the uncharged body gets the same charge and the charge is distributed equally.

(iii) Induction: When a uncharged body keep near the charged body, the uncharged body gets the same amount of charge but opposite in sign.  

(a) When a small tack of charge Q is lowered into the hole, then due to the process of induction, the charge on the inner surface of the shell is - Q.

(b) Due to the process of conduction, the charge on the outer surface of the shell is Q.

The charge on the inner surface of the shell is negative whereas the charge on the outer surface of the shell is positive.

Due to the process of induction the inner surface of the shell creates negative charge because when a uncharged body bring near to the charged body, the uncharged body gets the same amount of charge but opposite in sign.

While on the other hand, there is no charge interaction with the outer surface so it remains positively charge so we can conclude that the charge on the inner surface of the shell is negative whereas the charge on the outer surface of the shell is positive.

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