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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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Bobby is riding his bike down the road at a speed of 10 miles per hour. Ahead of him, he sees another rider, moving in the same

vekshin1

They will be travelling slower than 10mph.
if they were travelling at the same speed then they would stay an equal distance apart.
if they were travelling fatser then they would be getting further away more quickly than Bobby is catching up.
maybe they are travelling at 5mph but I'd say it's a safer option to chose under 10mph

4 0

3 years ago

Read 2 more answers

What is the first semiconductor

madam [21]

English "natural philosopher" (the contemporary term for physicist) Michael Faraday is renowned for his discovery of the principles of electro-magnetic induction and electro-magnetic rotation, the interaction between electricity and magnetism that led to the development of the electric motor and generator. The unit of measurement of electrical capacitance - the farad (F) - is named in his honor. Faraday's experimental work in chemistry, which included the discovery of benzene, also led him to the first documented observation of a material that we now call a semiconductor. While investigating the effect of temperature on "sulphurette of silver" (silver sulfide) in 1833 he found that electrical conductivity increased with increasing temperature. This effect, typical of semiconductors, is the opposite of that measured in metals such as copper, where conductivity decreases as temperature is increased. In a chapter entitled "On Conducting Power Generally" in his book Experimental Researches in Electricity Faraday writes "I have lately met with an extraordinary case ... which is in direct contrast with the influence of heat upon metallic bodies ... On applying a lamp ... the conducting power rose rapidly with the heat ... On removing the lamp and allowing the heat to fall, the effects were reversed." We now understand that raising the temperature of most semiconductors increases the density of charge carriers inside them and hence their conductivity. This effect is used to make thermistors - special resistors that exhibit a decrease in electrical resistance (or an increase in conductivity) with an increase in temperature. Next Milestone Contemporary Documents Faraday, M. Experimental Researches in Electricity, Volume 1. (London: Richard and John Edward Taylor, 1839) pp.122-124 (para. 432). Note: This section appears on different pages in later editions of the book. The material in the book is reprinted from articles by Faraday published in the Philosophical Transactions of the Royal Society of 1831-1838. More Information Hirshfeld, Alan W. The Electric Life of Michael Faraday. Walker & Company (March 7, 2006). Friedel, Robert D. Lines and Waves: Faraday, Maxwell and 150 Years of Electromagnetism. Center for the History of Electrical Engineering, Institute of Electrical and Electronics Engineers (1981).

3 0

4 years ago

Ted Clubber Lang. A hook in boxing primarily involves horizontal flexion of the shoulder while maintaining a constant angle at t

il63 [147K]

Answer:

15 m/s or 1500 cm/s

Explanation:

Given that

Speed of the shoulder, v(h) = 75 cm/s = 0.75 m/s

Distance moved during the hook, d(h) = 5 cm = 0.05 m

Distance moved by the fist, d(f) = 100 cm = 1 m

Average speed of the fist during the hook, v(f) = ? cm/s = m/s

This can be solved by a very simple relation.

d(f) / d(h) = v(f) / v(h)

v(f) = [d(f) * v(h)] / d(h)

v(f) = (1 * 0.75) / 0.05

v(f) = 0.75 / 0.05

v(f) = 15 m/s

Therefore, the average speed of the fist during the hook is 15 m/s or 1500 cm/s

6 0

3 years ago

A particle traveling in a circular path of radius 300 m has an instantaneous velocity of 30 m/s and its velocity is increasing a

hodyreva [135]

Answer:

5 m/s2

Explanation:

The total acceleration of the circular motion is made of 2 components: centripetal acceleration and linear acceleration of 4 m/s2. They are perpendicular to each other.

The centripetal acceleration is the ratio of instant velocity squared and the radius of the circle

$a_c = \frac{v^2}{r} = \frac{30^2}{300} = \frac{900}{300} = 3 m/s^2$

So the magnitude of the total acceleration is

$a = \sqrt{a_c^2 + a_l^2} = \sqrt{3^2 + 4^2} = \sqrt{9 + 16} = \sqrt{25} = 5 m/s^2$

4 0

4 years ago

A teacher walks 5m north of his desk, then we walks 6m south.

sergey [27]

11m if you add 6+5 you get 11 but of course you need the “m” in the mix so 11m but correct me if I’m wrong.

8 0

3 years ago