Answer:
Explanation:
The heat from the Sun gets to the surface of the Earth by radiation and not by convection because:
i. Radiation does not require material medium for its propagation: Since the space between the Sun and Earth is a vacuum ( i.e it is an empty space), then the only method for the heat from to Sun to get to the Earth is by radiation. This method does not require a material medium, while convection is a method that requires material medium for its propagation.
ii. Radiation occurs without heating the intervening medium: During the propagation of the heat from the Sun to the Earth, the space between the two heavenly bodies is not heated up. Some fraction of the heat after hitting the surface of the Earth get reflected back into the Earth's atmosphere. While in convection, the medium would have been heated up in the process.
A man stands still on a moving walkway that is going at a speed of 0.2 m/s to
the west. What is the velocity of the man according to a stationary observer?
A. 0.2 m/s north
B. 0.2 m/s west
C. 0.2 m/s South
D. 0.2 m/s east
When,a man stands still on a moving walkway that is going at a speed of 0.2 m/s to the west,then the velocity of the man according to a stationary observer would be 0.2 m/s west,Therefore, the correct answer would be option B.
What is Velocity?The total displacement covered by any object per unit of time is known as velocity. The velocity of an object is depend on the magnitude as well as the direction of the object.
the mathematical expression for velocity is given by
velocity = total displacement /time
The speed and velocity of the object are very different from each other because speed does not depend upon the direction of the moving object but velocity depends on the magnitude of speed as well as the direction of the moving object.
As per given in the problem a man stands still on a moving walkway that is going at a speed of 0.2 m/s to the west therefore from the perspective of a stationary observer the velocity of man would be 0.2 m/s towards West.
Hence the correct options for the problem would be option B.
Learn more about Velocity from here
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The unit of work in terms of Newton and metre is _______
Answer:
Joule
Explanation:
the unit of work is Joule determined by the letter J.
Answer:
JouleExplanation:
Joule is defined as the work done by a force of one newton causing a displacement of one meter. Sometimes, newton-metre (N-m) is also used for measuring work.
300 ml of a gas at 27°C is Cooled at -3°c at Constant pressure the final volume is plzz answer fast i will mark brainliest
Answer:V₁=300ml
T₁=27°C
V₂=?
T₂= -3°C
as we know
V₁T₁=V₂T₂
By putting values in formula
300ml×27°C=V₂×(-3°C)
300ml×27°C/-3°C=V₂
8100ml/-3=V₂
-2700ml=V₂
or V₂= -2700ml
Two solid cubes have the same Mass but their edges are in the ratio of 4:1. What isthe ratio of their densities?
Let m be the mass of both cubes. If the smaller cube has side length x, then its volume is x ³. The side lengths of the larger cube have length 4x, so the larger cube's volume is (4x)³ = 64x ³, or 64 times as large as the smaller cube.
The first cube has a density of m/x ³, while the larger one has a density of m/(64x ³) = 1/64 m/x ³, so the ratio of densities is (1/64):1, or 1:64 (larger cube to smaller cube).
can ya pls answer dis rq!
Answer:
I don't even know can u tell me how to ask questions
4 A student says that he has made a magnetic field with some iron filings. What would
you say to him?
Answer:
Yes but no
Explanation:
Here the kid cant say that he has created s magnetic field as iron fillings do not have magnetic properties
define simple machine
Answer:
simple machine, any of several devices with few or no moving parts that are used to modify motion and the magnitude of a force in order to perform work. ... The simple machines are the inclined plane, lever, wedge, wheel and axle, pulley, and screw.
what is measurement?
Answer:
The comparison of unknown quantity with known quantity is called measurement
Answer:
the size, length or amount of something is a measurement.
Explanation:
Measurements help in daily life and are important to development, accuracy and making decisions.
Please help me. I need this in a few hours.
Answer:
A) The population of prey is greater than that of predator
the gravitational force between two masses at distance of 2.5×10^6 metre is 250 Newton . what should be distance between them to reduce the gravitational force by half?
Answer:
distance between should be 1.25 × 10^6 m
Explanation:
Force is proportional to separation distance.
[tex]250 \: newtons = 2.5 \times {10}^{6} \: metres \\ ( \frac{1}{2} \times 250) \: newtons = d \\ \\ d = \frac{125 \times 2.5 \times {10}^{6} }{250} \\ d = 1.25 \times {10}^{6} \: metres[/tex]
Answer:
distance between should be 1.25×10^6.
Explanation:
force Is proportional to separation .
mrk above answer branilest .
The rate of chage of displacement is called __________
Answer:
Velocity is the rate of change of displacement.
An airplane flying at 116 m/s. E, is accelerated uniformly at the rate of 9.2 m/s2, E, for 13 s. What is its final velocity in m/s?
Answer:
235.6m/s
Explanation:
you have to use one of the kinematic formulas the best that suits the question given in this case you can use v=u+at.since the time, acceleration and initial velocity have been given in the question
v=116+(9.2)13^2
v=116+119.6
=235.6m/s
I hope this helps
The capacity of an RD bottle is 100 cc and its mass is 45 g. Find the mass of the bottle when it is filled with a liquid of density 600 kg/m3.
Answer:
The capacity of an RD bottle is 100cc and its mass is 45g. Find the mass of the bottle when it is filled with a liquid of density 600kg/[tex]m^{3}[/tex]
EXPLANATION:
100cc=100[tex]cm^{3}[/tex]
density of liquid=600Kg/ =0.6gm/
so mass of 100cc liquid will be m=d×V=0.6×100=60gm
So mass of bottle filled with liquid will be bottle+liquid=45gm+60gm=105gm
Answer is 105gm.
A train travels 600 kilometers in 1 hour. What is the train's velocity in meters/second?
here's the answer to your question
Define SI units. Also mention their importance. SI unit The
Answer:
SI unit is an internationally accepted system and have the same value all over the world .
I don't know the importance sotry
Answer:
SI unit is an internationally accepted system that have same value all over the world.
what is the role of the communicator in a dc generator?
A) it keeps the electric current flowing in one direction
B) it keeps the magnetic fields of the permanent magnet steady
C) it causes the magnetic fields of the permanent magnets to reverse
D) it causes the electric current to constantly reverse its direction
Answer:
C
Explanation:
Answer:
A)
Explanation:
it keeps the electric current flowing in one direction
define one standard kg
Answer:
The mass of platinum iridium rod whose diameter and height are equal an kept at international bureau of weight and measurement in Paris of France is called as one standard kg.
define inertia.mention it's types
Answer:
It is the inability of the body to change by itself its state of rest or uniform motion or direction. Types of Inertia- It is of three types-(1)Inertia of rest (2) Inertia of motion(3) Inertia of direction. (1) Inertia of rest - It is the inability of the body to change by itself its state if rest.
what is the relation between centre of gravity and stability
Explanation:
tilting it will raise the height of its center of gravity.
Why does the weight of a body differ on different celestial bodies of the universe?
What do is mean by environment friendly behaviour?
Why is velocity proportial to pressure?
Answer:
Pressure and velocity are inversely proportional to each other because if pressure increase, the velocity decrease to keep the algebraic sum of potential energy, kinetic energy and pressure constant.
What is 98.907 rounded to 1 significant figure?
The answer to the digits rounded to one significant figure is 100.
Significant figures are the most important figures in a number of digits.
The closer a digit is to the beginning of a number, the more important or significant it is.
But, the rule for rounding up a set of numbers to the first significant or to one significant figure is that:
If the next number is 5 or more, we round up.If the next number is 4 or less, we do not round up.From the numbers 98.907, 9 is the most significant digit followed by 8.
8 is greater than 5 so we should round up by adding one to 9 making the number 100.
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help me with this one
Answer:
may be d)45°
Explanation:
Which of the globes in Figure 7.9 will light up?
pls someone help me pls…. and pls explain to me how
Answer:
1.12 × 10⁴ m/s
Explanation:
The escape velocity of the object v = √(2GM/R) where G = gravitational constant = 6.67 × 10⁻¹¹ Nm²/kg², M = mass of the Earth = 6 × 10²⁴ kg and R = radius of the Earth = 6.4 × 10⁶ m
Since v = √(2GM/R)
Substituting the values of the variables into the equation, we have
v = √(2GM/R)
v = √(2 × 6.67 × 10⁻¹¹ Nm²/kg² × 6 × 10²⁴ kg/6.4 × 10⁶ m)
v = √(13.34 × 10⁻¹¹ Nm²/kg² × 6 × 10²⁴ kg/6.4 × 10⁶ m)
v = √(80.04 × 10⁻¹¹ × 10²⁴Nm²/kg/6.4 × 10⁶ m)
v = √(80.04 × 10¹³Nm²/kg ÷ 6.4 × 10⁶ m)
v = √(80.04 ÷ 6.4 × 10¹³ ÷ 10⁶Nm/kg)
v = √(12.50625 × 10⁷ Nm/kg)
v = √(125.0625 × 10⁶ Nm/kg)
v = 11.18 × 10³ m/s
v = 1.118 × 10 × 10³ m/s
v = 1.118 × 10⁴ m/s
v ≅ 1.12 × 10⁴ m/s
A certain superconducting magnet in the form of a solenoid of length 0.28 m can generate a magnetic field of 7.0 T in its core when its coils carry a current of 80 A. The windings, made of a niobium-titanium alloy, must be cooled to 4.2 K. Find the number of turns in the solenoid.
Answer:
The number of turns in the solenoid is 19506.
Explanation:
Length of solenoid, L = 0.28 m
Magnetic field, B = 7 T
Current, I = 80 A
Let the number of turns is N.
The formula used to find the magnetic field is
[tex]B = \frac{\mu 0N I}{L}\\\\7 = \frac{4 \times 3.14\times 10^{-7}\times N\times 80}{0.28}\\\\N = 19506[/tex]
Calculate the efficiency of the following appliances:
1. A radiator that converts 1000) of electrical energy into 900J
of heat energy and 100J of light energy
2. A torch that converts 100J of chemical energy into 35) of
light energy and 65J of heat energy
3. A car that converts 10,000J of chemical energy into 6000) of
kinetic energy and 4000J of heat energy.
4. An energy saver light converts 1,000J of electrical energy
into 7003 of light energy and 300J of heat energy.
5. A speaker converts 100J of electrical energy into 50J of
sound energy and 50J of heat and kinetic energy.
we
Answer:
1. The efficiency of the radiator is 90 %
2. The efficiency of the torch is 65 %
3. The efficiency of the car is 40 %
4. The efficiency of the energy saver is 70 %
5. The efficiency of the speaker is 50 %
Explanation:
Efficiency = (Useful energy out ÷ Total energy in) × 100 J
1. Useful energy = 900 J
The total energy in = 1000 J
The efficiency of the radiator = ((900 J)/(1,000 J)) × 100 % = 90 %
2. Useful energy = 65 J
The total energy in = 100 J
The efficiency of the torch = ((65 J)/(100 J)) × 100 % = 65 %
3. Useful energy = 4,000 J
The total energy in = 10,000 J
The efficiency of the car = ((4,000 J)/(10,000 J)) × 100 % = 40 %
4. Useful energy = 700 J
The total energy in = 1,000 J
The efficiency of the energy saver = ((700 J)/(1,000 J)) × 100 % = 70 %
5. Useful energy = 50 J
The total energy in = 100 J
The efficiency of the speaker = ((50 J)/(100 J)) × 100 % = 50 %
If the box of 500N is placed over the land of area of 2m²,what pressure is experted by the box on the land?
Answer:
250 Pa or N/m^2
Explanation:
Pressure(P)=F/A=500/2=250 Pa or N/m^2
there is a dropping of a coconut of 2kg mass. the speed of the coconut at the moment before it hits the ground is 40m s-1.
calculate the kinetic energy of the coconut at the moment.
We know
[tex]\boxed{\sf K.E=\dfrac{1}{2}mv^2}[/tex]
m denotes to mass v denotes to velocity[tex]\\ \sf\longmapsto K.E=\dfrac{1}{2}\times 2\times 40^2[/tex]
[tex]\\ \sf\longmapsto K.E=40^2[/tex]
[tex]\\ \sf\longmapsto K.E=1600J[/tex]
