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IRISSAK [1]
3 years ago
9

Which identifies that a chemical reaction has occurred?

Physics
1 answer:
mixer [17]3 years ago
8 0
A change of colour, heat being released or fizzing (a gas being released)
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Barnard's star is a near neighbor of the Sun whose properties we know quite well. It is a type M4V with absolute magnitude 13.22
vitfil [10]

Answer:

The star is at a distance of 100 parsecs.

Explanation:

The distance can be determined by means of the distance modulus:

M - m = 5log(d) - 5  (1)

Where M is the absolute magnitude, m is the apparent magnitude and d is the distance in units of parsec.

Therefore, d can be isolated from equation 1

log(d) = (M - m + 5)/5

Then, Applying logarithmic properties it is gotten:

d = 10^{(M - m + 5)/5}  (2)

The absolute magnitude is the intrinsic brightness of a star, while the apparent magnitude is the apparent brightness that a star will appear to have as is seen from the Earth.

Since both have the same spectral type is absolute magnitude will be the same.

Finally, equation 2 can be used:

d = 10^{(13.22 - 8.22+ 5)/5}  

d = 100 pc    

Hence, the star is at a distance of 100 parsecs.

Key term:

Parsec: Parallax of arc seconds

8 0
3 years ago
A force has direction and contact
dalvyx [7]

Answer:

A force has both magnitude and direction, making it a vector quantity. It is measured in the SI unit of newton (N). Force is represented by the symbol F. The original form of Newton's second law states that the net force acting upon an object is equal to the rate at which its momentum changes with time.

Other units: dyne, pound-force, poundal, kip, kilopond

SI unit: newton (N)

Common symbols: F→, F, F

7 0
3 years ago
Part 1 - Basic Equations
bearhunter [10]

Answer:

1. λ = 2 L, 2.  v = 2L f₁ , 3.    v = √ T /μ², 4.   μ = 2,287 10⁻³ kg / m , 5.   Δv / v = 0.058 , 6.    Δμ /  μ = 0.12 , 7. Δ μ = 0.3  10⁻³ kg / m ,

8.  μ = (2.3 ±0.3)  10⁻³ kg / m

Explanation:

The speed of a wave is

            v = λ f                1

Where f is the frequency and λ the wavelength

     

The speed is given by the physical quantities of the system with the expression

            v = √ T /μ²                   2

1) The fundamental frequency of a string is when at the ends we have nodes and a maximum in the center, therefore this is

                 L = λ / 2

                 λ = 2 L

2) For this we substitute in equation 1

              v = 2L f₁

3) let's clear from equation 2

             

The speed of a wave is

            v = λ f₁

Where f is the frequency and Lam the wavelength

The speed is given by the physical quantities of the system with the expression

           v = √ T /μ²                            2

4) linear density is

           μ = T / (2 L f₁)²

           μ = 5.08 / (2 0.812 29.02)²

           μ = 2,287 10⁻³ kg / m

We maintain three significant length figures, so the result is reduced to

           μ = 2.29 10⁻³ kg / m

5) the speed of the wave is

            v = 2 L f₁

The fractional uncertainty is

         Δv / v = ΔL / L + Δf₁ / F₁

         Δv / v = 0.02 / 0.812 + 1 / 29.02

         Δv / v = 0.024 + 0.034

         Δv / v = 0.058

6) the equation for linear density is

              μ = T / (2 L f₁)²

             Δμ / μ = 2 ΔL / L + 2Δf₁ / f₁

The tension is an exact value therefore its uncertainty is zero ΔT = 0

            Δμ / μ = 2 0.02 / 0.812 + 2 1 / 29.02

             Δμ /  μ = 0.12

7) absolute uncertainty

           Δ μ = e_{r}   μ

           Δ μ = 0.12 2.29 10⁻³ kg / m

           Δ μ = 0.3  10⁻³ kg / m

8)

           μ = (2.3 ±0.3)  10⁻³ kg / m

8 0
3 years ago
Which statement is true about acceleration?
dmitriy555 [2]
C is the correct answer.
6 0
4 years ago
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What is equilibrium<br> pls answer i know but need to confirm
Verdich [7]

Answer:

a state in which opposing forces or influences are balanced.

Explanation:

6 0
3 years ago
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