An electric heater takes 1.2kwh in 30min at 120V having an efficiency of 99%.The heat energy required boil a certain amount of water is 99KJ.If the current taken by heater is 20 amp at 120V.Find the time required to boil water?

Answer: The statement that correctly identified the difference between laws and theories is

(LAWS describe phenomena (things happening in nature), while THEORIES explain why phenomena exist.)

Explanation:

LAW in the field of natural sciences is defined as a statement which describes a remarkable event( things happening in nature) after repeated close observations.

Example of law in natural science includes:

--> law of conservation of mass

--> law of conservation of energy

THEORY in the field of natural sciences is the explanation of these remarkable events after repeated observations. This helps in bringing together facts and hypothesis (ideas that can be tested with further scientific observations).

Example of theory includes:

--> kinetic theory of matter

--> Dalton's atomic theory.

Answer:

in short the answer is b

Explanation:

took nthe test

Answer:

Positive

Explanation:

Because there is no electrons.

Answer:

A. The points on the end of magnet, where the magnetic field is strongest.

Explanation:

A magnet is a substance that has the ability to attract magnetic materials, e.g iron, steel etc. It comprises of two poles (north-N and south-S) each at its two ends. The N-pole and S-pole are the points on a magnet that have the strongest magnetic field. The magnetic fields originates from the north pole, and terminates in the south pole of a magnet.

When the poles of two different magnets are brought close together, attraction or repulsion may occur.

The option that defines the magnetic poles is the points on the end of the magnet, where the magnetic field is strongest.

Attracting other iron-containing objects or aligning themselves in a magnetic field.

There are two poles of the magnet;

1. the North Pole.

2. the South Pole.

The same poles repel each other, while the opposite poles attract each other.

Thus, the correct option is A.

To learn more about the magnet, refer to the link;

brainly.com/question/13026686

Answer:

55miles per hour

Explanation:

speed=distance/time

speed=192.5miles/3.5hours

speed=55miles per hour

Answer:

55miles per hour

Explanation:

Simply divide the number you travelled with the hour you will get the answer.

Answer:

See below

Explanation:

ICT " Information and the communication technology" can be used in sectors like Telecommunications. ADB support for telecommunications and ICT is changing lives across the region. ...

ICT in Education. ICT can improve the efficiency and quality of education at all levels. ...

ICT in Public Sector Management. ...

ICT in Health. ...

ICT in Agriculture and Food Security.

( hope it helped <3 )

Answer:

d

Explanation:

Answer:

1.00 m is a more accurate measured length.

Explanation:

Denote length of the table by L.

For L=1.0 m, there is one significant digit after the decimal.

Care 1: When one more significant digit after decimal considered, the exact number can be from 0.95 to 1.05.

So, the possible span of error [tex]\Delta E_1= 1.05-0.95= 0.1m[/tex]

For L=1.00 m, there is two significant digits after the decimal.

Case 2: When one more significant digit after decimal considered, the exact number can be from 0.095 to 1.005.

So, the possible span of error [tex]\Delta E_2= 1.005-0.095= 0.01m[/tex]

Case 3: For L=1.000 m, there is three significant digits after the decimal.

When one more significant digit after decimal considered, the exact number can be from 0.0095 to 1.0005.

So, the possible span of error [tex]\Delta E_3= 1.0005-0.0095= 0.001m[/tex]

As [tex]\Delta E_1 >\Delta E_2>\Delta E_3[/tex]

So, the least error is in the third case when L=1.00m, hence, L= 1.00m is more accurate.

Answer:

B. They show the pattern made by the magnetic field lines around the

magnets

Explanation:

Using iron fillings, the pattern of the magnetic field lines around a bar magnet can be known.

Magnetic field lines are the line of force around a bar magnet.

Answer:

B

Explanation: E Z

Answer:

a) F = 353.2 N

b) [tex]F_{f} = 147.2 N [/tex]

   a = 4.21 m/s²

Explanation:

a) The minimum force necessary to start moving the box s given by:       

[tex]\Sigma F = 0[/tex]

[tex] F - \mu_{s}N = 0 [/tex]

[tex] F = \mu_{s}mg [/tex]

Where:

F: is the force applied to move the box

μs: is the static coefficient of friction = 0.6          

m: is the mass = 60 kg

g: is the gravity = 9.81 m/s²

[tex] F = 0.6*60 kg*9.81 m/s^{2} = 353.2 N [/tex]

b) The acceleration is:

[tex] F - F_{f} = ma [/tex]

[tex] F - \mu_{k}mg = ma [/tex]              

[tex] a = \frac{F - \mu_{k}mg}{m} = \frac{400 N - 0.25*60 kg*9.81 m/s^{2}}{60 kg} = 4.21 m/s^{2} [/tex]

Now, the friction force is:

[tex] F_{f} = \mu_{k}mg = 0.25*60 kg*9.81 m/s^{2} = 147.2 N [/tex]

I hope it helps you!    

Answer is D.the distance between the focal point and the center of the lens.

Answer:

it is B i took the test and got it wrong when someone said it was A

Explanation:

it is the one that says the sizing of the objects will appear unusual

Answer:

the 3rd one im pretty sure

Explanation:

Answer:the answer is answer 3

Explanation:

Answer:

Explanation:

The force acting on an object given it's mass and acceleration can be found by using the formula

force = mass × acceleration

From the question we have

force = 2 × 2

We have the final answer as

Hope this helps you

Answer: Distance-time graph is the plot of distance travelled by a body against time.  Below is an example of a distance-time graph, if it is a straight horizontal line than the body is stationary, its speed is zero, if the line is diagonal than its moving with a constant speed and if it is anything other than a straight line then the speed is varying. Distance-Time Graph for Uniform Motion Let us now consider a distance-time graph in which the body is moving with uniform motion. A body is said to be in uniform motion when the body covers the equal distance in equal time intervals. Let’s consider a time interval of 1 second, If a body covers 10 meters in the first 1-second then it should cover 10 meters in every second from there on, this will indicate that the body is in uniform motion.

Explanation: I hoped that helped!!

Answer:

Y = 176.4 m

Explanation:

For the height of cliff we will analyze the vertical motion. We will apply the 2nd equation of motion:

Y = V₀y*t + (0.5)gt²

where,

Y = Height = ?

V₀y = Initial Vertical Velocity = 0 m/s (since, ball is thrown horizontally)

t = time = 6 s

g = 9.8 m/s²

Therefore,

Y = (0 m/s)(6 s) + (0.5)(9.8 m/s²)(6 s)²

Y = 176.4 m

Answer:

an object in motion stays in motion an object at rest stays in rest

Explanation:

Answer:

16 m/s sir

Explanation:

because i am in collage

Answer:  Kinetic energy is energy that an object has as a result of its motion. Potential energy is stored energy that has not yet been released.

Explanation:  All moving objects possess kinetic energy, which is determined by the mass and speed of the object. Potential energy is the energy an object has as a result of its position.

Answer:

9828 coulombs

Explanation:

z = [tex]\sqrt{3x^2 + 3y^2}[/tex]

Relation between the cartesian and polar coordinates

x = r cos ∅

y = r sin ∅

z = [tex]\sqrt{3x^2 + 3y^2}[/tex] = [tex]\sqrt{3r}[/tex]

next we calculate the surface charge density of the cone

б ( r, ∅ ) = xyz^2 = 3r^4 sin∅ cos∅

Charge given as

Q = ∫ б(r,∅ )ds

   = ∫ б(r,∅ ) [tex]\sqrt{1 +( \frac{dz}{dx})^2 + (\frac{dz}{dx} )^2 } dA[/tex]

after integration

Q  = ∫ б(r,∅ ) 2dA

Attached below is the remaining part of the solution

Answer:

Many ionic substances will dissolve completely in water to form an aqueous solution of cations and anions; this solution will conduct electricity.

Explanation:

Answer:

Many ionic substances will dissolve completely in water to form an aqueous solution of cations and anions; this solution will conduct electricity.

Explanation:

Answer:

Lc = 242 [m]

Explanation:

The circumference is defined as the circumference length of a circle, this length can be calculated by means of the following equation.

[tex]L_{c}=2*\pi *r[/tex]

where:

Lc = circumference length = 220 [m]

r = radius [m]

Now we can clear r

[tex]r=\frac{L_{c}}{2*\pi } \\\\r = \frac{220}{2*\pi }\\\\r = 35.01 [m][/tex]

Now we can determine the outer radius with the inner diameter plus the width of the track.

R = r + 3.5

R = 35.01 + 3.5 = 38.51 [m]

The outer circumference is:

[tex]L_{c} = 2*\pi *38.51 \\L_{c} = 242 [m][/tex]

Answer:

Explanation:

Pressure = Force/Area

Given

Pressure = 690,000Pa

Area will be the area of the circular section of the cylindrical tank

Area of a circle =πd²/4

Area of a circle =π(0.15)²/4

Area of a circle = 3.14(0.0225)/4

Area of a circle = 0.07065/4

Area of a circle = 0.0176625m²

Get the force

Force = Pressure * Area

Force = 690,000* 0.0176625

Force = 12,187.125N

Hence the force applied by the air inside the tank is 12,187.125N

Answer:

0.20 G

Explanation:

The given parameters are;

The magnetic field strength of planet X = 0.70 G

The location of a probe in relation to the vertical wire = 50 m

The measurement of a probe placed 50 mm east of a vertical wire = 0.50 G

The location of the probe = 20 mm east of the vertical wire

Based on the given parameter,  the wire is a current carrying conductor with a magnetic field acting tangent to the magnetic field lines.

Given that the measured Earth magnetic field reduces, we have that the magnetic field of the wire cancels the magnetic field of the Earth

As the probe moves closer to the wire the measured magnetic field in the southern direction reduces

When the probe is placed 20 mm from the wire, the magnetic field reduces to 20/50 × 0.50 G = 0.20G

Answer:55,000 kg•m/s

Explanation:

Explanation:

P.E=MGH

(1) P.E=5×10(G)×3

= 150 kg m^/s^ ( ^ =sqaure)

(2) P.E=5×10×6

= 300 kg m^/s^

Hope it helps, just remember the formula u can solve any question regarding gravition of earth (P.E=Mgh)

Answer:

B)

Explanation:

Answer:

F = 39.2 N   (hand force) and    N = 68.6 N (shoulder force)

Explanation:

In this exercise we must use the rotational and translational equilibrium conditions, we have several forces: the weight (W) of the pole applied at its geometric center, the load (w1) at one end, the shoulder support (N) 60 cm from the load and hand force (F) at the other end of the pole

Let's set the reference system at the fit point of the shoulder

     ∑ τ = 0

We will assume that the counterclockwise turns are positive

    w₁ 0.60 + W 0.1 + F₁ 0 - F 0.4 = 0

all distances are measured from the support of the man (x₀ = 0.60 m)

    F = (w₁ 0.60 + W 0.1) / 0.4

    F = (m₁ 0.6 + m 0.1) g / 0.4

let's calculate

    F = (2.6 0.6 + 0.4 0.1) 9.8 / 0.4

    F = 39.2 N

this is the force that the hand must exert to keep the system in balance

We apply the translational equilibrium condition

    -w₁ -W + N - F = 0

     N = w₁ + W + F

     N = (m₁ + m) g + F

let's calculate

     N = (2.6 + 0.4) 9.8 + 39.2

     N = 68.6 N

Answer:

a.) 20.4 h

b.) 3.46 km/h

Explanation:

Given that an English Channel is 35 km wide at its narrowest point, which is where most swimmers attempt to cross north to south from England to France. The current across this portion of the English Channel runs at about 2 km/h east to west.

a.) If a swimmer has a relative velocity to the shore of 3 km/h north to south, The resultant velocity (Vr) will be achieved by using Pythagoras theorem  

Vr = [tex]\sqrt{2^{2} + 3^{2} }[/tex]

Vr = [tex]\sqrt{4 + 9}[/tex]

Vr = [tex]\sqrt{12}[/tex]

Vr = 3.46 m/s

To get how long it take her to cross the 35 km distance, Let us first find acceleration by using third equation of motion.

[tex]V^{2} = U^{2} + 2aS[/tex]

Where U = 0

Substitute all the parameters into the equation

[tex]3.46^{2} = 2 x a x 35[/tex]

11.97 = 70a

a = 11.97/70

a = 0.17 km/h^2

The time can be found by using equation

V = U + at

let U = 0

3.46 = 0.17t

t = 3.46/0.17

t = 20.35h

b. What must be her velocity relative to the water if she has a velocity of 3 km/h north to south relative to the shore?

her velocity relative to the water will be

Vr = [tex]\sqrt{2^{2} + 3^{2} }[/tex]

Vr = [tex]\sqrt{4 + 9}[/tex]

Vr = [tex]\sqrt{12}[/tex]

Vr = 3.46 m/s

Answer:

The Science of Round Bubbles

But once a bubble is sealed and removed from the wand, the tension in the bubble shrinks it to the smallest possible shape for the volume of air inside of it. That's a sphere, which is the familiar round shape we see when bubbles float through the air.

Explanation: