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puteri [66]
3 years ago
11

Which change is the best example of a physical change?

Physics
1 answer:
murzikaleks [220]3 years ago
3 0
The answer would be a nail rusting, but really it could be any of these.
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How is an electromagnet different from a bar magnet?
Reptile [31]
The answer for the question is c


5 0
3 years ago
Read 2 more answers
Imagine an alternate universe where the value of the Planck constant is . In that universe, which of the following objects would
HACTEHA [7]

Question: The planck constant was not given. In this calculation, planck constant of 6.62607*10^-9 Js  is used for the calculation.

Answer:

(a) A virus -------------Classical

(b) A buckyball -----Classical

(c) A mosquito ------ Quantum

(d) A turtle  ------------Quantum

Explanation:

 Calculating the wavelength using the formula;

λ= h/(mv)

where

λ= Wavelength

h = Planck Constant = 6.62607*10^-9 Js

m = mass in kg

v = velocity in m/s

Virus size = 280. nm = 2.80*10⁻⁷ m

a)

A Virus:

m = 9.4 x 10-17 g 9.4*10⁻²⁰ kg

v = 0.50 µm/s = 5 *10⁻⁷ m/s

h = 6.62607*10^-9 Js

Virus size = 280 nm = 2.80*10⁻⁷ m

Substituting into the formula; we have

λ= h/(mv)

λ= 6.62607*10^-9/ (9.4*10⁻²⁰* 5 *10⁻⁷)

  = 6.62607*10^-9/4.7*10^-26

  = 1.4*10^17 m

Classical : Wavelength is bigger than it's size

(b)

A buckyball

m = 1.2 x 10-21 g = 1.2 *10⁻²⁴ kg

V = 37 m/s

Size = 0.7 nm = 7*10⁻¹⁰ m

Substituting into the formula, we have

λ= h/(mv)

λ= 6.62607*10^-9/ ( 1.2 *10⁻²⁴* 37)

  =  6.62607*10^-9/4.44*10^-23

  = 1.49 *10^14 m

Classical : Wavelength is bigger than it's size

(c)

A mosquito

Mass = 1.0 mg = 1*10⁻⁶ kg

v = 1.1 m/s

Size =  6.3 mm = 6.3*10⁻³ m

Substituting into the formula, we have

λ= h/(mv)

λ= 6.62607*10^-9/ (  1*10⁻⁶* 1.1)

  =  6.62607*10^-9/1.1*10^-6

  = 6.02*10^-3 m

Quantum Approach: The wavelength and the size are comparable

(d)

A turtle

Mass = 710. g = 0.71 kg

Size =  22. cm = 0.22 m

V =  2.8 cm/s. = 0.028 m/s

Substituting into the formula, we have

λ= h/(mv)

λ= 6.62607*10^-9/ (  0.71* 0.028)

  = 6.62607*10^-9/0.01988

   = 3.33*10^-7 m

Quantum Approach: The wavelength and the size are comparable

8 0
3 years ago
A bullet is fired horizontally at a height of 1.3 meters and a velocity of 950 m/s. How long was the bullet in the air?
seropon [69]

Answer:

<em>The bullet was 0.52 seconds in the air.</em>

Explanation:

<u>Horizontal Motion </u>

It occurs when an object is thrown horizontally with a speed v from a height h.

The object describes a curved path ruled exclusively by gravity until it hits the ground.

To calculate the time the object takes to hit the ground, we use the following equation:

\displaystyle t=\sqrt{\frac{2y}{g}}

Note it doesn't depend on the initial velocity but on the height.

The bullet is fired horizontally at h=1.3 m, thus:

\displaystyle t=\sqrt{\frac{2\cdot 1.3}{9.8}}

\displaystyle t=\sqrt{\frac{2.6}{9.8}}

t = 0.52 s

The bullet was 0.52 seconds in the air.

3 0
3 years ago
What is the relationship between thermal energy and conduction convection and radiation
lapo4ka [179]
The higher the thermal energy the faster the conduction convection and radiation take place as the particles have more kinetic (movement) energy
4 0
3 years ago
1. What kind of light phenomena happen due to the refraction of light upon hitting the small crystals that make up cirrus or cir
Rama09 [41]

1. The light phenomena happen due to the refraction of light upon hitting the small crystals that make up cirrus or cirrostratus clouds is called Sundogs.

2.A light phenomena which are formed when light passes through clouds and strikes the ice crystals in them is called Halos.

3.A light phenomenon formed from the combination of several light properties like refraction, reflection, and dispersion is Rainbow.

4.  Rainbow are created after a rain shower and Sun light.

5. A visible accumulations of tiny water droplets or ice crystals.

in the Earth’s atmosphere are called Clouds.

6. There are seven colors in a rainbow.

7. The kind of rainbows are formed when light strikes small raindrops with almost the same size are Supernumerary rainbows.

8.The kind of rainbows are formed when two inner reflections are done instead of one; this causes the reversal of colors in a secondary rainbow in comparison to a primary rainbow are Secondary rainbows.

9. A reflective surface that is curved inward and away from the light source is concave mirror.

10. The kind of mirror are curved outward like the bottom

of a spoon is convex mirror.

<h3>What is reflection?</h3>

When a light strikes on a shiny surface, it reflects back the light ray in the same medium. The phenomenon is called reflection and the ray is called the reflected ray.

Thus, all the questions are answered.

Learn more about reflection.

brainly.com/question/2254222

#SPJ1

8 0
2 years ago
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