11. Why do dark surfaces absorb radiation better than light surfaces?

1 answer:

7 0

When an electromagnetic wave hits a surface the photons transmit part of the energy to the molecules of the surface. When parts of the electromagnetic waves are reflected depending on the wavelength that is reflected our eyes perceive the object as having a lighter or darker color. The more wavelengths are reflected the lighter the color of the object will be. The more wavelengths are absorbed the darker the object will appear to be. Therefore, those materials that absorb more wavelengths will be dark and those that absorb fewer wavelengths will appear lighter.

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Force due to gravity. While JWST is in orbit, the Earth will be at a distance of 1.494 x 109 m from the telescope, and the Sun w

Alona [7]

Answer:

the gravitational force JWST will feel from the Sun is 37.785 Newton { leftward }

Explanation:

Given that;

distance of earth from the telescope r1 = 1.494 × 10⁹ m

and the Sun will be 1.49598 × 10¹¹ m further away

so r2 = r1 + 1.49598 × 10¹¹

r2 = 1.494 × 10⁹ m + 1.49598 × 10¹¹ m = 1.51092 × 10¹¹ m

mass of sun Ms = 1.9884 × 10³⁰ kg

mass of earth Me = 5.945× 10²⁴ kg

mass of JWST Mj = 6500 kg

What is the gravitational force JWST will feel from the Sun (strength and direction)?

the gravitational force of the sun will be attractive based on Newton law of gravitational force; so

Fjs = GMjMs / r2²

constant G = 6.674 × 10⁻¹¹ Nm²/kg²

Force on the JWST by the sun will be;

Fjs = GMjMs / r2² { leftward}

we substitute

Fjs = [(6.674 × 10⁻¹¹ Nm²/kg²)(6500 kg )(1.9884 × 10³⁰ kg)] / (1.51092 × 10¹¹ m)²

= (8.62587804 × 10²³) / ( 2.28287925 × 10²² )

= 37.785 Newton { leftward }

Therefore, the gravitational force JWST will feel from the Sun is 37.785 Newton { leftward }

7 0

3 years ago

Two forces, one of 100 ponds and the other 150 pounds act on the same object, at angles of 20°and 60°, respectively, withthe pos

soldi70 [24.7K]

<h2>Resultant is 235.54 pounds at an angle 44.16° to X axis.</h2>

Explanation:

Forces are 100 pound and 150 pound and angles with x axis are 20°and 60°.

That is force 1 is 100 pound with x axis at 20°

F₁ = 100 cos 20 i + 100 sin 20 j

F₁ = 93.97 i + 34.20 j

That is force 2 is 150 pound with x axis at 60°

F₂ = 150 cos 60 i + 150 sin 60 j

F₂ = 75 i + 129.90 j

F₁ + F₂ = 93.97 i + 34.20 j + 75 i + 129.90 j

F₁ + F₂ = 168.97 i + 164.10 j

$\texttt{Magnitude = }\sqrt{168.97^2+164.10^2}\\\\\texttt{Magnitude = }235.54pounds\\\\\texttt{Angle = }tan^{-1}\left ( \frac{164.10}{168.97}\right )\\\\\texttt{Angle = }44.16^0$