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valentinak56 [21]

3 years ago

8

You can identify a pure substance if you know it's ?

2 answers:

PIT_PIT [208]3 years ago

8 0

If you know the physical properties

Vika [28.1K]3 years ago

7 0

If you know it's physical properties

You might be interested in

a 0.199 kg snowball moving west makes an inelastic collision with a 2.89 kg box moving 0.523 m/s west. afterward,they move west

kogti [31]

Answer:

The initial velocity of the snowball was 22.21 m/s

Explanation:

Since the collision is inelastic, only momentum is conserved. And since the snowball and the box move together after the collision, they have the same final velocity.

Let $m_1$ be the mass of the ball, and $v_1$ be its initial velocity; let $m_2$ be the mass of the box, and $v_2$ be its velocity; let $v_f$ be the final velocity after the collision, then according to the law of conservation of momentum:

$m_1v_1+m_2v_2=v_f(m_1+m_2)$ .

From this we solve for $v_1$ , the initial velocity of the snowball:

$\boxed{v_1=\frac{v_f(m_1+m_2)-m_2v_2}{m_1}}$

now we plug in the numerical values $m_1=0.199\:kg$ , $m_2=2.89\:kg$ , $v_2=0.523\:m/s$ , and $v_f=1.92\:m/s$ to get:

$v_1=\frac{1.92*(0.199+2.89)-2.89*0.523}{0.199}$

$\boxed{v_1=22.21\:m/s}$

The initial velocity of the snowball is 22.21 m/s.

<em>P.S: we did not take vectors into account because everything is moving in one direction—towards the west.</em>

4 0

3 years ago

The order of elements in the periodic table is based on

vladimir1956 [14]

A, the number of protons in the nucleus.
The atomic number tells us the amount of electrons and protons in an atom.

7 0

3 years ago

Which of the following animals have adapted to live in the arctic tundra? (Select all that apply.)

sashaice [31]

Answer:

no way I had that question too :-O anyways here's the answer

Explanation:

willow ptarmigan and Walia ibex

5 0

3 years ago

A 30,000kg train moves at 45m/s How how much kinetic energy with the train have?

nordsb [41]

Answer:

30,375,000

Explanation:

1/2 x m x v^2

1/2(30000)(45)^2

6 0

4 years ago

A rock band playing an outdoor concert produces sound at 120 dB 5.0 m away from their single working loudspeaker. What is the so

joja [24]

ANSWER:100dB

f<em>rom the sound intensity level,the sound intensity is calculated as:</em>

<em /> $\beta$ <em>₁=</em> $\beta$ <em>=(10dB)㏒₁₀(l₁/l₀)</em>

<em>inserting numbers:</em>

<em>120dB=(10dB)㏒₁₀[l₁/10⁻¹²W/m⁸] or 12=㏒₁₀[l₁/(10⁻¹²)W/m²</em>

<em>Getting the antilog of both sides and obtain 10¹²=l₁(10⁻¹²W/m²)which </em>

<em>can be used to solve for l₁ and get</em>

<em> l₁=(10⁻¹²W/m²)(10¹²)=1 W/m²</em>

<em>since the sound intensity is related to the power and that the power does not change,the sound intensity at any other point can be solved.Plugging-in</em>

<em>ᵃ = 4πr²,into P=l₁ₐ₁=l₂ₐ₂ and get:</em>

<em>l₂=l₁(r₁/r₂)² =(1W/m²)(5/35) =2.04×10⁻²W/m²</em>

<em>since we know the sound intensity at the sound point 2r,the sound intensity level at the point can be solved.We have:</em>

<em> </em> $\beta$ <em>₂=</em> $\beta$ <em>=(10dB)㏒₁₀(l₂/l₀)=(10dB)㏒₁₀(2.04×10⁻²/1×10⁻²)</em>

<em> </em> $\beta$ <em>₂=(10dB)㏒₁₀(2.04×10¹⁰)</em>

<em /> $\beta$ <em> =(10dB)[㏒₁₀(2.04)+㏒₁₀(10¹⁰)]=10dB[0.32+10]=103dB=100dB</em>

<em />

3 0

4 years ago