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3 years ago

What does the blackboard do when white light falls on it?

1 answer:

5 0

Actually a black board has all colours in light or white light . So when light falls on it board absorbs all colours because all are present so no light is reflected back. That is the case, and so it will appear black as it absorbs all colours of light that fall on it .

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A floating leaf oscillates up and down two complete cycles in one second as a water wave passes by. The wave's wavelength is 10

postnew [5]

Answer:

C) 20 m/s

Explanation:

Wave: A wave is a disturbance that travels through a medium and transfers energy from one point to another, without causing any permanent displacement of the medium itself. Examples of wave are, water wave, sound wave, light rays, radio waves. etc.

The velocity of a moving wave is

v = λf ............................ Equation 1

Where v = speed of the wave, λ = wave length, f = frequency of the wave.

Given: f = 2 Hz (two complete cycles in one seconds), λ = 10 meters

Substituting these values into equation 1

v = 2×10

v = 20 m/s.

Thus the speed of the wave = 20 m/s

The right option is C) 20 m/s

7 0

4 years ago

If the volume of the balloon is 500 m3m3 and the surrounding air is at 15.0 ∘C∘C, what must the temperature of the air in the ba

Tresset [83]

Answer:

Temperature of the air in the balloon = 272°C

Explanation:

Given:

Volume of balloon = 500 m³

Air temperature = 15° C = 273 + 15 = 288 K

Total weight = 290 kg

Density of air = 1.23 kg/m³

Find:

Temperature of the air in the balloon

Computation:

Density of hot air = Density of air - [Total weight / Volume of balloon]

Density of hot air = 1.23 - [290 - 500]

Density of hot air = 0.65 kg/m³

[Density of hot air][Temperature of the air in the balloon] = [Density of air][Air temperature ]

Temperature of the air in the balloon = [(1.23)(288)]/(0.65)

Temperature of the air in the balloon = 544.98

Temperature of the air in the balloon = 545 K

Temperature of the air in the balloon = 545 - 273 = 272°C

8 0

3 years ago

VOLLEYBALL TRUE OR FALSE

Volgvan

I play high school volleyball so i know this.

Its: True

True

False

3 0

4 years ago

Read 2 more answers

I shared a picture of the problem. It’s a basic Physics question and an Algebra question.

julia-pushkina [17]

Hence the expression of ω in terms of m and k is

$\omega = \sqrt{\frac{k}{m}$

Given the expressions;

$T_s = 2 \pi \sqrt{\frac{m}{k} } \ and \ T_s = \frac{2 \pi}{\omega}$

Equating both expressions we will have;

$2 \pi \sqrt{\frac{m}{k} } = \frac{2 \pi}{\omega}$

Divide both equations by 2π

$\frac{2 \pi\sqrt{\frac{m}{2 \pi} } }{2 \pi}=\frac{\frac{2 \pi}{\omega} }{2\pi}\\\sqrt{\frac{m}{2 \pi} } = \frac{1}{\omega}\\$

Square both sides

$(\sqrt{\frac{m}{k} } )^2 = (\frac{1}{\omega} )^2\\\frac{m}{k} = \frac{1}{\omega ^2} \\\omega ^2 = \frac{k}{m}$

Take the square root of both sides

$\sqrt{\omega ^2} =\sqrt{\frac{k}{m} } \\\omega = \sqrt{\frac{k}{m}$

Hence the expression of ω in terms of m and k is

$\omega = \sqrt{\frac{k}{m}$

3 0

3 years ago

What is the kinetic energy in Joules of a 1,500kg car traveling at 75mph?What is the kinetic energy in Joules of a 1,500kg car t

Sergio039 [100]

Answer: 2812500 joules

Explanation:

Mass of car = 1500kg

Velocity of car = 75mph

Kinetic energy = ?

Recall that kinetic energy is the energy possessed by a moving object, and it depends on its mass M and velocity, V

Thus, Kinetic energy = 1/2 x mv^2

= 1/2 x 1000kg x (75mph)^2

= 0.5 x 1000kg x (75mph)^2

= 500 x 5625

= 2812500 joules

Thus, the car travels with a kinetic energy of 2812500 joules

5 0

3 years ago

What does the blackboard do when white light falls on it?​

What does the blackboard do when white light falls on it?