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2 years ago

Describe some tests that could be done to determine what an unknown substance is.

Physics

2 answers:

valentina_108 [34]2 years ago

6 0

Answer:

Simple chemical tests can be used to identify the presence of various elements or classes of molecules (Tollen's test). ... Electron spin resonance (ESR): Also referred to as electron paramagnetic resonance (EPR), this method uses the spins of unpaired electrons in molecules to determine structure

natima [27]2 years ago

3 0

Answer:

by finding melting and boiling points

Explanation:

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An inductor is connected in series to a fully charged capacitor. Which of the following statements are true? Check all that appl

Luba_88 [7]

Answer:

As the capacitor is discharging, the current is increasing

Explanation:

Lets take

C= Capacitance

L=Inductance

V=Voltage

I= Current

The total energy E given as

$E=\dfrac{IL^2}{2}+\dfrac{CV^2}{2}$

We know that total energy E is conserved so when electric energy 1/2 CV² decreases then magnetic energy 1/2 IL² will increases.

It means that when charge on the capacitor decreases then the current will increase.

As the capacitor is discharging, the current is increasing

3 0

3 years ago

If you wanted the pitch of a horn to drop relative to an observer, which way would you move the horn, relative to where that obs

Vladimir [108]

We assume that horn releases sound of constant frequency. In order for observer to observe different frequency either horn or observer or both must move.

This happens due to Doppler effect. It states that when position of source of sound and observer relative to each other changes, the observed frequency also changes. If the source emits sound of constant frequency than observed frequency will be either higher or lower than original.

When distance between source and observer increases the observed frequency will be lower. This is because same number of sound waves must cover greater distance so they have greater wavelength.
When distance between source and observer decreases the observed frequency will be higher. This is because same number of sound waves must cover smaller distance so they have smaller wavelength.

Wavelength and frequency are inversely proportional meaning when one increases the other drecreases.

From this explanation we can find answer for our question. <span>If we wanted the pitch of a horn to drop relative to an observer we need to move horn away from an observer.</span>

3 0

2 years ago

A motorist is driving at 20m/s when she sees that a traffic light 200m ahead has just turned red. She knows that this light stay

yuradex [85]

Answer:

5.71428571422 m/s

Explanation:

u = Initial velocity = 20 m/s

v = Final velocity

s = Displacement

a = Acceleration

Time taken = 15-1 = 14 s

Distance traveled in 1 second = $20\times 1=20\ m$

$s=ut+\frac{1}{2}at^2\\\Rightarrow 200-20=20\times 14+\frac{1}{2}\times a\times 14^2\\\Rightarrow a=\frac{2(180-20\times14)}{14^2}\\\Rightarrow a=-1.02040816327\ m/s^2$

$v=u+at\\\Rightarrow v=20-1.02040816327\times 14\\\Rightarrow v=5.71428571422\ m/s$

The speed as she reaches the light at the instant it turns green is 5.71428571422 m/s

4 0

3 years ago

Gumuhit ng paglalaruan ng<br>agawang sulok at ibigay ang bawat<br>sukat nito.

Anarel [89]

Answer:

there's a link to answer

Explanation:

there's a link to answer in another's persons response it helps a lot just click on it

8 0

2 years ago

QUESTION 1

lisabon 2012 [21]

Answer:

2 * 10^5 pa

Explanation:

Pressure = Force / Area

Each thigh bone has a cross sectional area of 10cm²

Both thigh bones :

2 * 10cm² = 20cm²

To m² : 20 * (0.01)²

20 * 0.0001 m² = 0.002 m²

Force = mass * acceleration due to gravity(g)

g = 10m/s² ;

Force = 40 * 10 = 400N

Pressure = 400 N / 0.002 m²

Pressure = 200,000 N/m² = 2 * 10^5 pascal

8 0

2 years ago