There are three fundamental forces that act at a distance. They are gravitational, electromagnetic and nuclear forces.
Answer: C. good reflector of heat
Explanation:
In space, sunlight transfers heat by radiation to objects and bodies and this includes satellites and astronauts. In addition, although the peak of the sun's emission is in the visible region of the electromagnetic spectrum, a part is also emitted in infrared (transferring thermal energy or heat) and ultraviolet (especially in the upper part of the Earth's atmosphere).
That is why in space missions, objects and many satellites are covered by thin layers or sheets that reflect this thermal energy and thus avoid damaging the equipment due to high temperatures.
In this sense, among the reflective materials used are aluminum, silver, copper and gold; the latter being the most used because it does not corrode or oxidize (unlike silver and copper) and is more malleable than aluminum.
On the other hand, <u>astronauts are also vulnerable to the effects of infrared radiation, especially their eyes</u>, since the human eye has no receptors in the infrared spectrum. <u>That is why the astronaut's helmet visor is covered with a thin layer of gold to avoid the dangerous effects of solar radiation.</u>
Answer:
Current, I = 0.54 A
Resistance, R = 201.6 ohms
Explanation:
Electric power is given in terms of current, I, and voltage, V, as:
P = I*V
I = P/V
The current flowing in the 60 W bulb will be:
I = 60/110 = 0.54 Amps
The resistance can be gotten by using an alternate formula for Power in terms of resistance:
P = V²/R
R = V²/P
R = 110²/60
R = 201.6 ohms
The 60W bulb has a current 0.54A flowing through it and a resistance of 201.6 ohms.
Decompose the forces acting on the block into components that are parallel and perpendicular to the ramp. (See attached free body diagram. Forces are not drawn to scale)
• The net force in the parallel direction is
∑ <em>F</em> (para) = -<em>mg</em> sin(21°) - <em>f</em> = <em>ma</em>
• The net force in the perpendicular direction is
∑ <em>F</em> (perp) = <em>n</em> - <em>mg</em> cos(21°) = 0
Solving the second equation for <em>n</em> gives
<em>n</em> = <em>mg</em> cos(21°)
<em>n</em> = (0.200 kg) (9.80 m/s²) cos(21°)
<em>n</em> ≈ 1.83 N
Then the magnitude of friction is
<em>f</em> = <em>µn</em>
<em>f</em> = 0.25 (1.83 N)
<em>f</em> ≈ 0.457 N
Solve for the acceleration <em>a</em> :
-<em>mg</em> sin(21°) - <em>f</em> = <em>ma</em>
<em>a</em> = (-0.457N - (0.200 kg) (9.80 m/s²) sin(21°))/(0.200 kg)
<em>a</em> ≈ -5.80 m/s²
so the block is decelerating with magnitude
<em>a</em> = 5.80 m/s²
down the ramp.
All of the elements<span> in Group Zero are </span>noble gases<span>. The list includes helium, neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). Don't think that, because these </span>elements<span> don't like to react, we don't use them.</span>