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3 years ago

The light from the Sun heats a metal surface. This is an example of what?

2 answers:

8 0

Radiation. That's perhaps the only way that energy gets from the Sun to the earth. The space between the two is a vacuum, so conduction is more or less out as is convection. There's no obvious sign of mirrors, so reflection seems to be out as well.

tekilochka [14]3 years ago

5 0

Answer: The correct answer is radiation.

Explanation:

There are three method of transfer of energy: conduction, convection and radiation.

In conduction, there is no actual movement of the particle. There is conduction in the solid. Heat is transferred from hotter end of an object to cold end of the particle.

In convection, there is actual movement of the particle. Both liquid and gases can transfer heat energy by convection.

In radiation, it does not require particles in its transfer of energy. In the given problem, the light from the Sun heats a metal surface. This is an example of radiation.

Therefore, the option is A.

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A constant power is supplied to a rotating disc .the relationship of angular velocity of disc and number of rotations made by th

Bogdan [553]

A rotating disc supplied with constant power where the relationship of the angular velocity of the disc and the number of rotations made by the disc is governed by Newton's second law for rotation. This law is specially made for rotating bodies which is extracted from Newton's second law of motion.

6 0

3 years ago

Two particles A and B start simultaneously from a Point P with velocities 20 m/s and 30 m/s respectively. A and B move with acce

zysi [14]

Answer:

20 m/s

Explanation:

Given

u(A) = 20 m/s
u(B) = 30 m/s
acceleration equal in magnitude but opposite in direction

Solving

Velocity of A at Q = 30 m/s
From, P to Q, Δv(A) = 30 - 20 = +10 m/s
Therefore, velocity of B at Q will be decreased by 10 as it is equal in magnitude but opposite in direction to A
Δv(B) = v(B at Q) - u(B at P)
-10 m/s = v(B at Q) - 30 m/s
v(B at Q) = 30 - 10 = 20 m/s

6 0

2 years ago

The force of air resistance acts to oppose the motion of an object moving through the air. A ball is thrown upward and eventuall

ozzi

Answer:

For a (1) net force will be greater than the weight of the ball

For b (2) net force will be lesser than the weight of the ball

Explanation:

For (a):

For a linear motion of a system, one must have to understand, according to Newtons first law of motion, which is also known as law of inertia, a body which is at motion will continue to move or a body at rest will continue to rest until an external force is applied to it. In the given case, when ball goes upward, one thing is for sure, the net force is greater than the weight of the ball, because three forces are applied during upward motion:

gravity or weight which is pulling the ball downward,

air resistance, which is also acting downward as it is creating friction between ball and air molecules, so creating hindrance in upward motion

External force to throw ball upward

Net Force = Upward force - Air friction - Weight

Since ball is going upward, so net force is greater than both weight and air friction which are pulling ball downward.

For (b):

For a linear motion of a system, one must have to understand, according to Newtons first law of motion, which is also known as law of inertia, a body which is at motion will continue to move or a body at rest will continue to rest until an external force is applied to it. In the given case, when ball goes downward, one thing is for sure, the net force is lesser than the weight of the ball, because two forces are applied during downward motion:

gravity or weight which is pulling the ball downward,

air resistance, which is acting upward as it is creating friction between ball and air molecules, so creating hindrance in downward motion

Net Force = Weight - Air friction

Since ball is going downward, so weight is greater than net force which is in this case is air friction which is pulling ball upward.

4 0

3 years ago

Yamel is heating up leftover mashed potatoes from Thanksgiving. She forgot to put gravy on them. So she puts the cold gravy on t

monitta

Answer:

The correct answer is - option A. The mashed potatoes will transfer heat into the gravy.

Explanation:

In this case, where Yamel heats the mashed potatoes but forgets to heat the gravy and put the cold gravy on the hot mashed potatoes. Heat always transfers from the high-temperature object to the low-temperature object. So the hot mashed potatoes will transfer the heat to the gravy according to option A. Cold is not a form of heat but the condition of absence of heat or very low temperature.

Thus, the correct answer is - option A. The mashed potatoes will transfer heat into the gravy.

3 0

2 years ago

What is Planck’s law?

Lyrx [107]

Answer:

The wavelength of the emitted radiation is inversely proportional to its frequency, or λ = c/ν. The value of Planck's constant is defined as 6.62607015 × 10−34 joule∙second.

Explanation:

Planck's quantum theory. According to Planck's quantum theory, Different atoms and molecules can emit or absorb energy in discrete quantities only. The smallest amount of energy that can be emitted or absorbed in the form of electromagnetic radiation is known as quantum.

Hope this helps!

3 0

3 years ago