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When humans look at the sky, it appears blue, but the Sun appears yellow. What causes this phenomenon?

otez555 [7]

Light behaves like a wave, and the different colors we perceive are the result of light hitting our eyes at different <em>wavelengths</em>. The air molecules in our atmosphere scatter this visible light, with a "preference" towards light of shorter wavelengths -- blue and violet light. Light of longer wavelengths (green, yellow, orange, red), doesn't pass through to us as visibly until later in the day, when the sun's light has more atmosphere to pass through before it reaches our eyes. The blue light becomes so scattered by the air molecules in its way at this point that we're finally able to see those yellows and reds coming through on our end.

6 0

4 years ago

The mean diameters of Mars and Earth are 6.9 ✕ 103 km and 1.3 ✕ 104 km, respectively. The mass of Mars is 0.11 times Earth's mas

Roman55 [17]

Answer:

(a) Ratio of mean density is 0.735

(b) Value of g on mars 0.920 $m,/sec^2$

(c) Escape velocity on earth is $3.563\times 10^4m/sec$

Explanation:

We have given radius of mars $R_{mars}=6.9\times 10^3km=6.9\times 10^6m$ and radius of earth $R_{E}=1.3\times 10^4km=1.3\times 10^7m$

Mass of earth $M_E=5.972\times 10^{24}kg$

So mass of mars $M_m=5.972\times\times 0.11 \times 10^{24}=0.657\times 10^{24}kg$

Volume of mars $V=\frac{4}{3}\pi R^3=\frac{4}{3}\times 3.14\times (6.9\times 10^6)^3=1375.357\times 10^{18}m^3$

So density of mars $d_{mars}=\frac{mass}{volume}=\frac{0.657\times 10^{24}}{1375.357\times 10^{18}}=477.69kg/m^3$

Volume of earth $V=\frac{4}{3}\pi R^3=\frac{4}{3}\times 3.14\times (1.3\times 10^7)^3=9.198\times 10^{21}m^3$

So density of earth $d_{E}=\frac{mass}{volume}=\frac{5.972\times 10^{24}}{9.198\times 10^{21}}=649.271kg/m^3$

(A) So the ratio of mean density $\frac{d_{mars}}{d_E}=\frac{477.69}{649.27}=0.735$

(B) Value of g on mars

g is given by $g=\frac{GM}{R^2}=\frac{6.67\times 10^{-11}\times0.657\times 10^{24}}{(6.9\times 10^6)^2}=0.920m/sec^2$

(c) Escape velocity is given by

$v=\sqrt{\frac{2GM}{R}}=\sqrt{\frac{2\times 6.67\times 10^{-11}\times 0.657\times 10^{24}}{6.9\times 10^6}}=3.563\times 10^4m/sec$

5 0

4 years ago

Read 2 more answers

A deer is running from a mountain lion when it encounters a fence that is 1.50 m high. Seeing the fence, the deer jumps, leaving

Novosadov [1.4K]

Answer:

Explanation:

Given

Initial Velocity (u)=13 m/s

angle $=29^{\circ}$

distance between fence and deer=2.5 m

We consider deer jump similar to projectile motion

equation of trajectory

$y=xtan\theta -\frac{gx^2}{2u^2(cos\theta )^2}$

$y=2.5tan(29)-\frac{9.8\times 2.5^2}{2\times 13^2\times (cos29)^2}$

$y=1.385-0.2368=1.148 m$

Thus deer will cross the fence with an difference in its jump and fence

1.5-1.148=0.351 m

$h_{max}=\frac{u^2sin^2\theta }{2g}$

$h_{max}=\frac{13^2\times (sin29)^2}{2\times 9.8}$

$h_{max}=2.02 m$

so deer rises during when it is over fence

8 0

4 years ago

Which is an example of potential en

SIZIF [17.4K]

a yoyo in someones hand is an example of potential energy

8 0

3 years ago

Read 2 more answers

The hierarchy of needs is the spectrum of needs ranging from basic ________ needs to ________ needs to self-actualization.

Zanzabum

The hierarchy of need was developed by Maslow. The pyramid is a motivational theory in psychology that argues that people is seeking to meet successively higher needs. The base of the pyramid is for the physiological needs to safety, belongingness, esteem, and finaly self-actualization.

3 0

3 years ago