2/​A mains electricity hairdryer has a resistance of 46 Ω and a current of 5 A flows through it when in use. What is the voltage across the hairdryer? (This is the mains voltage in the UK)




3/ What is the voltage across a lamp of resistance 4 Ω if a current of 2.5 A flows through it?

Please help :)

Answer:

0.82 m

Explanation:

Given:

v₀ᵧ = 4 m/s

aᵧ = -9.8 m/s²

Find: Δy when vᵧ = 0 m/s

vᵧ² = v₀ᵧ² + 2aᵧΔy

(0 m/s)² = (4 m/s)² + 2 (-9.8 m/s²) Δy

Δy = 0.82 m

The maximum height reached by the athlete is 0.82 meters.  The jump is not successful.

Answer:

yeah..

as we all know that the cheapest fuel is petrol because it is the last product of petroleum.

hope it helps...

Answer:

the formula for tension is mg + ma. T is equal to tension, N, kg-m/s^2

Explanation:

I hope it helps you

Answer:

Hey!

Your answer is...

T = mg + ma

Explanation:

T = tension, N, kg-m/s^2

m = mass, kg

g = gravitational force, 9.8 m/s^2

a = acceleration, m/s^2

HOPE THIS HELPS!!

Answer:

The answer is False

Hope this helps you

It is false that a neutral atom has the same number of protons as it does neutrons. The correct option is B.

The claim that "A neutral atom has the same number of protons as it does neutrons" is untrue. Protons and electrons in a neutral atom are equal in number, but neutron counts can change.

Electrons have a negative charge, whereas protons have a positive charge. A neutral atom has a net charge of zero because the protons' positive charge is balanced by the electrons' negative charge.

Neutrons don't have an electric charge, though. Within a single element, the amount of neutrons can change, giving rise to many isotopes.

Isotopes contain the same amount of protons, but their atomic masses vary depending on how many neutrons they have.

Thus, the correct option is B. False.

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Answer:

the resultant vector will be a null vector or with 0 magnitude

Explanation:

Answer:

8.43 m/s²

Explanation:

Average acceleration is the change in velocity over change in time.

a = Δv/Δt

First, convert km/h to m/s.

45 km/h = 12.5 m/s

500 km/h = 138.9 m/s

Now find the acceleration.

a = (138.9 m/s − 12.5 m/s) / 15.0 s

a = 8.43 m/s²

Answer:

Electric Potential Energy:

The energy that is needed to move a charge against an electric firld is called Electric Potential Energy

Electric Potential Difference:

The amount of work done in carrying a unit charge from one point to an other in an electric field is called Electric Potential Difference.

Relation:

Relation between Electric potential and electrical potential energy is given by

[tex]\delta V=\frac{PE}{q}[/tex]

Here PE represents Electric potential energy

and [tex]\delta V[/tex] is Electric potential difference

it means electric potential difference is the difference in electric potential energy divided by the charge.

Answer:

The two forms of energy that increase during the time after take off are;

1) The kinetic energy KE

1) The potential energy PE

Explanation:

1) Given that the airplane is accelerating, we have that the velocity, v, of the airplane is increasing, such that the we have the kinetic energy, KE, for a given mass, m, of the airplane increasing as follows;

KE₂ = 1/2×m×v₂² > KE₁ = 1/2×m×v₁²

2) Also, as the height, h, of the airplane increases during the ascent, we have that the potential energy increasing along side as follows;

PE₂ = m × g × h₂ > PE₁ = m × g × h₁

Therefore, the two forms of energy that increase during the time after take off are the kinetic  and the potential  energy.

Answer:

The length of the rope must be an integral multiple of the wavelength of the wave.

Explanation:

Answer:

The condition necessary for formation or a standing wave is that the length of the rope (or the length over which the wave is distributed) must be an integral multiple of the wavelength of the wave. Therefore, l=nλ where n is a positive integer.

Answer: 0.5N

Explanation:

Gravitational force is calculated using the formula :

F = Gm1m2/r^2

Where G is the gravitational constant (6.67 × 10^-11)

At a distance 'r' of 2metres apart:

Mass of objects are m1 and m2

Gravitational force 'F1' = 2N

Inputting values into the formula :

2 = Gm1m2 / 2^2 - - - - - (1)

At a distance 'r' of 4meters apart:

Mass of objects are m1 and m2

Gravitational force 'F2' = y

Inputting values

F2 = Gm1m2 / 4^2 - - - - - (2)

Dividing equations 1 and 2

2 = Gm1m2 / 2^2 ÷ F2 = Gm1m2 / 4^2

2 / F2 = (Gm1m2 / 4) / (Gm1m2 / 16)

2 / F2 = (Gm1m2 / 4) × (16 / Gm1m2)

2/F2 = 16 / 4

Cross multiply

2 × 4 = 16 × F2

8 = 16F2

F2 = 8/16

F2 = 0.5N

Answer:

The time taken by the car to come at rest is 2.5 seconds

Explanation:

The parameters given are;

Speed of bus = 72 km/hr

Distance at which bus stopped = 25 m

Given that the speed and the distance covered before stopping are j=known, we have;

v² = u² - 2·a·s

Where:

v = Final velocity = 0

a = Deceleration of the bus

s = Distance covered while decelerating = 23 m

u = Initial  velocity = 72 km/hr = 20 m/s

Which gives;

0² = (20 m/s)² - 2×a×25 m

20² = 2×a×25 m

a = 20²/(2×25) = 8 m/s²

The time, t, it takes for the car to come at rest is given by the relation;

v = u - at

0 = 20 - 8×t

t = 20/8 = 2.5 s.

[tex]\mathfrak{\huge{\pink{\underline{\underline{AnSwEr:-}}}}}[/tex]

Actually Welcome to the Concept of the Work And Energy.

So we here use the formula as,

W= Mgh

so after solving we get as,

W = 0.686 Joules

Answer:Deforestation refers to the decrease in forest areas across the world that are lost for other uses such as agricultural croplands, urbanization, or mining activities. Greatly accelerated by human activities since 1960, deforestation has been negatively affecting natural ecosystems, biodiversity, and the climate. The UN’s Food and Agriculture Organization estimates the annual rate of deforestation to be around 1.3 million km2 per decade.

Explanation:

The negative effect of deforestation on the environment is desertification. The correct option is B.

Desertification is the process by which fertile land becomes desert, typically as a result of drought, deforestation, and inappropriate agriculture or land use practices. It occurs when land that was once able to support vegetation and life becomes increasingly dry, barren, and unable to sustain crops, livestock, or human populations. This can be due to natural causes such as prolonged droughts, but it is often exacerbated by human activities such as deforestation, overgrazing, and soil degradation. Desertification can have devastating effects on the environment, leading to soil erosion, loss of biodiversity, and reduced productivity of the land. It can also cause social and economic problems, such as displacement of people, food shortages, and conflicts over resources.

Here in the question,

Deforestation is the clearing of trees and other vegetation from an area, leading to the loss of habitat and biodiversity, and disruption of water cycles. It can also cause soil erosion, which can result in the depletion of soil nutrients, reduced productivity, and eventually lead to desertification. Additionally, deforestation contributes to climate change by releasing carbon dioxide into the atmosphere, which can cause global warming and other environmental problems. Habitat restoration, soil production, and urbanization are not negative effects of deforestation but can be impacted by it.

Therefore, The correct answer is B i. e Desertification.

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Answer:

18 m

Explanation:

Given:

v₀ = 6 m/s

v = 12 m/s

a = 3 m/s²

Find: Δx

v² = v₀² + 2aΔx

(12 m/s)² = (6 m/s)² + 2 (3 m/s²) Δx

Δx = 18 m

Answer:

Part A:

They will repel each other because same poles repel each other.

Part B)

They will attract each other because different poles attract each other..

Answer: 390, right

explanation: The net force is just the sum of all of these forces acting on an object. ... This equation is the sum of n forces acting on an object. The magnitude of the net force acting on an object is equal to the mass of the object multiplied by the acceleration of the object, as shown in this formula.

the net force acting on the buggy is 390 and The net force is pointing to the is right

The following information should be considered:

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Explanation:

I think its because when you join the weight of the 4 tyres it could sum up to the weight of the car

Answer:

this is because; as area increases, pressure decreases.

Explanation:

there are four tires in a car and these tires are equally flat, this helps to reduce the force acting upon it and helps to withstand the huge weight of the car.

Answer:

1:281.25m

2:75m/s

Explanation:

using the equation

[tex]v^{2} = u^{2} + 2gs[/tex]

at maximum height v is zero so using that you can make s the subject of the formula

[tex]h \: max = u^{2} \div \: 2g[/tex]

so substitute the velocity 75 and the constant g-10m/s^2

as for the returning velocity we say displacement is zero since you go and come back the same distance

so

[tex]v = { + or - }u[/tex]

u is the initial speed in this case it's positive since going in the direction of gravity

Answer:

Explanation:

Angle of rotation of the flat polished surface [tex]\theta[/tex] = 15°

angle of incidence i = 20°

Since the polished surface is turned at an angle of 15°, the angle of reflection

r = 2[tex]\theta[/tex] (Note that the angle of rotation only have effect of the angle of reflection)

r = 2*15 = 30°

The angle between the reflected ray and the incident ray will be equal to the sum of the angle of incidence and the angle of reflection i.e i+r

The angle between the reflected ray and the incident ray = 20°+ 30° = 50°

Answer:

38.7°

Explanation:

Draw a free body diagram of the car.  There are three forces:

Weight force mg pulling down,

Normal force N pushing up perpendicular to the incline,

and friction force Nμ pushing parallel up the incline.

Sum of forces in the perpendicular direction:

∑F = ma

N − mg cos θ = 0

N = mg cos θ

Sum of forces in the parallel direction:

∑F = ma

Nμ − mg sin θ = 0

Nμ = mg sin θ

μ = (mg sin θ) / N

μ = (mg sin θ) / (mg cos θ)

μ = tan θ

Given μ = 0.8:

θ = tan⁻¹(0.8)

θ = 38.7°

Answer:

Explanation:

Check the complete diagram n the attachment below

a) The angle of incidence on a plane surface is the angle between the incidence ray and the normal ray acting on a plane surface. The normal ray is the ray perpendicular to the surface while the incidence ray is the ray striking a plane surface.

According to the diagram, the angle of reflection r₂ on M₂ is 90°-g where g is the angle of glance.

Given angle of glance on M₂ to be 40°, r₂ = 90-40 = 50°

According the second law of reflection, the angle of incidence = angle of reflection, therefore i₂ = r₂ = 50° (on M₂)

Also ∠OO₂O₁ =  ∠OO₁O₂ = 40° (angle of glance on M₁){alternate angle}

The angle of incidence on M₁ = 90° - 40° = 50°

b) The angle of incidence to the surface of M₁(∠PO₁A)will be the angle of glance on M₁ which is equivalent to 40°

Answer:

0.40

Explanation:

Given that :

the mass of the caer = 250 kg

initial speed = 14 m/s

final speed = 0 m/s

distance  s = 25 m

Using the equation of motion

[tex]v^2 = u^2 + 2as[/tex]

making a the subject of the formula ; we have:

[tex]v^2-u^2 = 2as[/tex]

[tex]a= \dfrac{v^2-u^2 }{2 \ s}[/tex]

[tex]a= \dfrac{(0)^2-(14)^2 }{2 \ (25)}[/tex]

[tex]a= \dfrac{0-196 }{50}[/tex]

[tex]a= \dfrac{-196 }{50}[/tex]

a = -3.92 m/s²

However; the relation for the coefficient of the kinetic static friction can be expressed as:

[tex]f= \mu_k *mg= ma[/tex]

[tex]f= \mu_k *g= a[/tex]

[tex]f= \mu_k = \dfrac{a}{g}[/tex]

[tex]f= \mu_k = \dfrac{3.92}{9.8}[/tex]

[tex]f= \mu_k = 0.40[/tex]

Answer:

Sound is a form of wave . Wave is defined as a periodic disturbance in medium.

Reasons:  

1. It follows all properties of light at a boudary.

2. Noise cancelling headphones.

3. It carry energy from one place to another.

Explanation:

I hope this will help you guy.

Sound wave is a mechanical type of wave because it requires a material medium for its propagation.

The following are three reasons sound is classified as a wave.

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Answer:

Explanation:

slit separation d = .3 x 10⁻³ m

screen distance D = 4.35 m

fringe width = 6.4 x 10⁻² / 9

= .711 x 10⁻² m

a ) Interference pattern on the screen is created due to interference of two light waves coming from two slits and falling in screen . When they fall on different points on the screen they travel different distance . This is called path difference . When their path difference is equal to their wave length or its integral multiple , they reinforce each other and at that point the brightness increases . On the other hand when at a point the path difference is equal to odd multiple of half wavelength , they kill or destroy each other and darkness is found at that point . In this way dark band and bright band appear on the screen . This is called interference pattern .

b )

Fringe width  = λ D / d

Putting the values

.711 x 10⁻² = λ x 4.35 /  0.3 x 10⁻³

λ = .049 x 10⁻⁵

= 490 x  10⁻⁹

= 490 nm

The colour of this wavelength will be blue .

Answer:

Option B

Explanation:

Kinetic Energy is the energy possessed by the body due to "motion".

The answer is:

Answer:

Of course, with a triangle with a 90° angle, a right triangle, you can simply use pythagoras theorem  (a2+b2=c2)  then SOH-CAH-TOA to solve for the angle  (θ=Cos−1(adjacenthypotenuse)) .

But what if it isn't a right triangle? The cosine rule works for all triangles, even if they don't have a 90° angle.

a2=b2+c2−2(b)(c)Cos(A)  

Where a is the missing side, and A is the angle opposite to side a.

With this rule, we can find a missing angle or a missing side to any type of triangle, assuming you have the needed variables.

Explanation:

The box acted upon by the force of 5 N will move on a frictionless surface, with the condition S = P + Q.

The effect of a push or a pull on the body is known as force. The main types of forces include friction forces, nuclear forces, and gravitational forces. For instance, when a hand strikes a wall, the wall exerts a force on the hand as well as the hand exerting a force on the wall. Newton was given several laws to comprehend force.

Given: with a triangle with a 90° angle, a right triangle, you can simply use Pythagoras theorem  (a2+b2=c2)  then SOH - CAH - TOA to solve for the angle  (θ=Cos−1(adjacent hypotenuse)).

The cosine rule works for all triangles, even if they don't have a 90° angle.

a2=b2+c2−2(b)(c)Cos(A)  

A is the angle opposite to side a,

With this rule, we can find a missing angle or a missing side to any type of triangle, assuming you have the needed variables.

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Answer:

Wavelength =50 m

Explanation:

Given:

n=20

t=10sec

V=25m/s

Wavelength =?

Solution:

Wavelength = frequency ×velocity ---> eq 1

Time period=time/no of vibrations

T=10/20=0.5sec

Frequency =1/Time period(T)

f=1/0.5=2

Put the value of frequency in eq 1

Wavelength =2×25

Wavelength =50m...

Hope you understand!

Have a nice day!

Answer:

Energy=3.1times 10^-17 J

Rest mass: 6.2 kg

Speed: 47.5 m/s

Wavelength: 2.659 times 10^-6

Momentum: 67.3 kg(m/s)

Explanation:

Explanation:

Given:

v₀ₓ = 15 m/s cos 20° = 14.10 m/s

aₓ = 0 m/s²

v₀ᵧ = 15 m/s sin 20° = 5.13 m/s

aᵧ = -9.8 m/s²

t = 1.5 s

Find: Δx and Δy

Δx = v₀ₓ t + ½ aₓ t²

Δx = (14.10 m/s) (1.5 s) + ½ (0 m/s²) (1.5 s)²

Δx = 21.1 m

Δy = v₀ᵧ t + ½ aᵧ t²

Δy = (5.13 m/s) (1.5 s) + ½ (-9.8 m/s²) (1.5 s)²

Δy = -3.33 m