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2 years ago

How do scientists know our universe is older than 6500 years?

1 answer:

5 0

This is because astronomers have discovered that the Crab Nebula is 6500 light years from earth. This means it takes 6500 earth years for light to get from the Crab Nebula to earth. Therefore, if we are able to observe the Crab Nebula and beyond it then it means that earth has been in existence for 6500 years and over.

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If the temperature of a volume of ideal gas increases for 100°C to 200°C, what happens to the average kinetic energy of the mole

mina [271]

Answer: $\Delta E=2.0715\times 10^{-21} J$

Explanation:

Given

Temperature of the gas is increased from 100 to 200

Also we know that average kinetic energy of the molecules is

$E=\frac{3}{2}\cdot \frac{R}{N_A}T$

Where

R=Gas constant

$N_A$ =Avogadro's number

T=Temperature in kelvin

$\frac{R}{N_A}=1.381\times 10^{-23}$

So kinetic energy increases by

$\Delta E=\frac{3}{2}\times 1.381\times 10^{-23}\left ( 200-100\right )$

$\Delta E=2.0715\times 10^{-21} J$

8 0

2 years ago

Explain velocity ratio. Explain and define the efficiency of a machine

Norma-Jean [14]

Velocity ratio is also defined as the ratio of a distance through which any part of a machine moves, to that which the driving part moves during the same time. An object has a mechanical advantage if it exerts a force higher than the velocity ratio.

8 0

2 years ago

A 12,000kg. railroad car is traveling at +2m/s when it

ivann1987 [24]

Answer:

The final velocity of the two railroad cars is 1.09 m/s

Explanation:

Since we are given that the two cars lock together it shows that the collision is inelastic in nature. The final velocity due to inelastic collision is given by

$\mathrm{V}=\frac{V 1 M 1+V 2 M 2}{M 1+M 2}$

where

V= Final velocity

M1= mass of the first object in kgs = 12000

M2= mas of the second object in kgs = 10000

V1= initial velocity of the first object in m/s = 2m/s

V2= initial velocity of the second object in m/s = 0 (given at rest)

Substituting the given values in the formula we get

V = 2×12000 + 0x100012000 + 10000= 2400022000= 1.09 m/s

$\mathrm{V}=\frac{2 \times 1200+0 \times 1000}{12000+10000}=\frac{24000}{22000}=1.09 \mathrm{m} / \mathrm{s}$

Which is the final velocity of the two railroad cars

8 0

2 years ago

Jenise is buying a car for $7,020. The TAVT rate is 9.1%.

djyliett [7]

Answer:

$7,658.82

Explanation:

Sales Tax Calculations:

Sales Tax Amount = Net Price x (Sales Tax Percentage / 100)

Total Price = Net Price + Sales Tax Amount

Net Price: $ 7,020.00

+Sales Tax (9.1%): $ 638.82

Total Price: $ 7,658.82

Therefore, the amount of tax that Jenise has to pay on her car is $7,658.82

8 0

2 years ago

What is silviculture?

expeople1 [14]

Sivilculture isis the art and science of managing forests for desired outcomes.

8 0

2 years ago