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3 years ago

What famous equation describes the energy of stars?

Physics

1 answer:

Ksivusya [100]3 years ago

7 0

Answer:

E=mc2

Explanation:

It explains that in their interiors, atoms fuse together, creating energy.

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Describe the conditions necessary for equilibrium on a balance.

tia_tia [17]

Answer:

Explanation:

A body under concurrent forces (concurrent forces are forces with their line of action acting at a point) is said to be in equilibrium if the sum total of the forces acting on the body is zero.

For forces acting on a balance, the sum of upward forces and the downward forced acting on the balance must be equal for the balance to be in equilibrium.

Also the sum of clockwise moment must be equal to the sum of anticlockwise moment acting on the balance.

Moment is the product of force and the perpendicular distance from the force to the pivot.

7 0

4 years ago

Can yall help me?

IceJOKER [234]

Explanation:

Ohm's law describes the relationship between voltage, current, and resistance.

V = IR

where V is voltage, I is current, and R is resistance.

A. At the original voltage:

V₁ = I₁ R₁

When the voltage is doubled and resistance stays the same:

2V₁ = I₁' R₁

Dividing the two equations:

2V₁ / V₁ = (I₁' / I₁) (R₁ / R₁)

2 = I₁' / I₁

So the new current is double the original current.

B. At the original voltage and resistance:

V₂ = I₂ R₂

When both the voltage and resistance are increased by a factor of 2:

2V₂ = I₂' (2R₂)

Dividing the two equations:

(2V₂ / V₂) = (I₂' / I₂) (2R₂ / R₂)

2 = (I₂' / I₂) (2)

1 = I₂' / I₂

So the new current is the same as the original current.

3 0

3 years ago

A tree falls in a forest. How many years must pass before the 14C activity in 1.03 g of the tree's carbon drops to 1.02 decay pe

just olya [345]

Answer:

t = 5.59x10⁴ y

Explanation:

To calculate the time for the ¹⁴C drops to 1.02 decays/h, we need to use the next equation:

$A_{t} = A_{0}\cdot e^{- \lambda t}$ (1)

where $A_{t}$ : is the number of decays with time, A₀: is the initial activity, λ: is the decay constant and t: is the time.

To find A₀ we can use the following equation:

$A_{0} = N_{0} \lambda$ (2)

where N₀: is the initial number of particles of ¹⁴C in the 1.03g of the trees carbon

From equation (2), the N₀ of the ¹⁴C in the trees carbon can be calculated as follows:

$N_{0} = \frac{m_{T} \cdot N_{A} \cdot abundance}{m_{^{12}C}}$

where $m_{T}$ : is the tree's carbon mass, $N_{A}$ : is the Avogadro's number and $m_{^{12}C}$ : is the ¹²C mass.

$N_{0} = \frac{1.03g \cdot 6.022\cdot 10^{23} \cdot 1.3\cdot 10^{-12}}{12} = 6.72 \cdot 10^{10} atoms ^{14}C$

Similarly, from equation (2) λ is:

$\lambda = \frac{Ln(2)}{t_{1/2}}$

where t 1/2: is the half-life of ¹⁴C= 5700 years

$\lambda = \frac{Ln(2)}{5700y} = 1.22 \cdot 10^{-4} y^{-1}$

So, the initial activity A₀ is:

$A_{0} = 6.72 \cdot 10^{10} \cdot 1.22 \cdot 10^{-4} = 8.20 \cdot 10^{6} decays/y$

Finally, we can calculate the time from equation (1):

$t = - \frac{Ln(A_{t}/A_{0})}{\lambda} = - \frac {Ln(\frac{1.02decays \cdot 24h \cdot 365d}{1h\cdot 1d \cdot 1y \cdot 8.20 \cdot 10^{6} decays/y})}{1.22 \cdot 10^{-4} y^{-1}} = 5.59 \cdot 10^{4} y$

I hope it helps you!

7 0

4 years ago

Batteries can supply a steady flow of electrons. True False

Alecsey [184]

The answer is TRUE, batteries CAN supply a steady flow of electrons.

6 0

3 years ago

Why is sun the only star that can be seen during day time

hoa [83]

Explanation:

i think the sun is near the earth that's why we see the sun during the day and the moon is behind the sun so when it is in the night the moon will remove in front the sun and there will be night I hope it will help you

7 0

3 years ago