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2 years ago

Why are there time zones? What is there purpose?

Physics

1 answer:

ExtremeBDS [4]2 years ago

8 0

Answer:

Timezones exist because of rotation and revolution

Explanation:

As Earth rotates on its axis, it moves about 15 degrees every 60 minutes. After 24 hours, it has completed a full rotation of 360 degrees. The scientists used this information to divide the planet into 24 sections or time zones. Each time zone is 15 degrees of longitude wide.

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Is the refraction different entering medium that has a higher index of refraction compared to entering amedium that has a lower

oee [108]

Answer:

Yes

Explanation:

The speed of light when it travels through glass, diamond, etc, the light travels at different speed from the speed of light. Speed of the light in material is related to the index of refraction.

The change in speed which occurs when the light passes from one medium to the another is responsible for bending of the light which is called as refraction.

When the light goes into a medium with the higher index of the refraction, light bends towards normal. Conversely, if the light traveling goes from higher refractive index to lower refractive index, it will bend away from the normal.

Hence, the refraction is different in both the scenario.

6 0

3 years ago

M84, M87, and NGC 4258 all have accretion disks around their central black holes for which the rotational velocities have been m

givi [52]

Answer:

For M84:

M = 590.7 * 10³⁶ kg

For M87:

M = 2307.46 * 10³⁶ kg

Explanation:

1 parsec, pc = 3.08 * 10¹⁶ m

The equation of the orbit speed can be used to calculate the doppler velocity:

$v = \sqrt{\frac{GM}{r} }$

making m the subject of the formula in the equation above to calculate the mass of the black hole:

$M = \frac{v^{2} r}{G}$ .............(1)

For M84:

r = 8 pc = 8 * 3.08 * 10¹⁶

r = 24.64 * 10¹⁶ m

v = 400 km/s = 4 * 10⁵ m/s

G = 6.674 * 10⁻¹¹ m³/kgs²

Substituting these values into equation (1)

$M = \frac{( 4*10^{5}) ^{2} *24.64* 10^{16} }{6.674 * 10^{-11} }$

M = 590.7 * 10³⁶ kg

For M87:

r = 20 pc = 20 * 3.08 * 10¹⁶

r = 61.6* 10¹⁶ m

v = 500 km/s = 5 * 10⁵ m/s

G = 6.674 * 10⁻¹¹ m³/kgs²

Substituting these values into equation (1)

$M = \frac{( 5*10^{5}) ^{2} *61.6* 10^{16} }{6.674 * 10^{-11} }$

M = 2307.46 * 10³⁶ kg

The mass of the black hole in the galaxies is measured using the doppler shift.

The assumption made is that the intrinsic velocity dispersion is needed to match the line widths that are observed.

3 0

3 years ago

How would you describe the appearance of the substance after the phase change?

Leona [35]

Answer:

Substances can change phase—often because of a temperature change. At low temperatures, most substances are solid; as the temperature increases, they become liquid; at higher temperatures still, they become gaseous. The process of a solid becoming a liquid is called melting.

4 0

3 years ago

What are the potential out comes of force

AysviL [449]

Answer:

F in the definition of potential energy is the force exerted by the force field, e.g., gravity, spring force, etc. The potential energy U is equal to the work you must do against that force to move an object from the U=0 reference point to the position r.

Explanation:

5 0

2 years ago

Identify each picture as either an inelastic collision or elastic collision

Ivan

Answer:

Inelastic collision:

A collision in which there is a loss of Kinetic Energy due to internal friction of the bodies colliding.

Characteristics of an inelastic collision:

the momentum of the system is conserved
the momentum of the system is conservedloss of kinetic energy

In a perfectly elastic collision, the two bodies that collide with each other stick together.

Elastic collision:

A collision in which the kinetic energy of the two bodies, before and after the collision, remains the same.

Characteristics of elastic collision:

the momentum of the system is conserved
no loss of kinetic energy

In everyday life, no collision is perfectly elastic.

__________________

ANSWER:

Given examples:

Two cars colliding with each other form an example of inelastic collision.

Reason:

(They lose kinetic energy and come to a stop after the collision.)

A ball bouncing after colliding with a surface is an example of elastic collision

Reason:

(a very less amount of kinetic energy is lost)

7 0

2 years ago