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ANEK [815]
4 years ago
15

An atom contains 15 neutrons and has a mass number of 30. What is its atomic number? How did you determine the atomic number?

Physics
1 answer:
irinina [24]4 years ago
8 0

Answer:

15

Explanation:

The mass number is defined as the total number of protons and neutrons. The atomic number is total number of protons. And since we have the mass number and number of neutrons, we can use simple subtraction (30 - 15) to find that the atomic number is 15.

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An 80 g, 40 cm long rod hangs vertically on a frictionless, horizontal axle passing through its center. A 15 g ball of clay trav
fiasKO [112]

Answer:

θ  = 12.95º

Explanation:

For this exercise it is best to separate the process into two parts, one where they collide and another where the system moves altar the maximum height

Let's start by finding the speed of the bar plus clay ball system, using amount of momentum

The mass of the bar (M = 0.080 kg) and the mass of the clay ball (m = 0.015 kg) with speed (v₀ = 2.0 m / s)

Initial before the crash

      p₀ = m v₀

Final after the crash before starting the movement

     p_{f} = (m + M) v

     p₀ = p_{f}

     m v₀ = (m + M) v

     v = v₀ m / (m + M)

     v = 2.0 0.015 / (0.015 +0.080)

     v = 0.316 m / s

With this speed the clay plus bar system comes out, let's use the concept of conservation of mechanical energy

Lower

    Em₀ = K = ½ (m + M) v²

Higher

    E_{mf} = U = (m + M) g y

   Em₀ = E_{mf}

   ½ (m + M) v² = (m + M) g y

   y = ½ v² / g

   y = ½ 0.316² / 9.8

   y = 0.00509 m

Let's look for the angle the height from the pivot point is

    L = 0.40 / 2 = 0.20 cm

The distance that went up is

     y = L - L cos θ

     cos θ  = (L-y) / L

     θ  = cos⁻¹ (L-y) / L

     θ  = cos⁻¹-1 ((0.20 - 0.00509) /0.20)

      θ  = 12.95º

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3 years ago
A spaceship leaves a space station and emits a flash of light that travels at a speed of 300,000 km/s. The spaceship starts out
balandron [24]
The answer is number D
7 0
3 years ago
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Communicating results allows scientists to learn from each other's results.
sveta [45]

True, scientists often talk to each other to figure out if their results were similar and what they could have done better.

Although, talking to other scientists does have risks, other scientists could copy your work and further better it.

So, your final answer is TRUE, sorry for the long answer, I needed to have a word count about 20 characters and then I got carried away! lol

3 0
3 years ago
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An airplane travels at 300 mi/h south for 2.00 h and then at 250 mi/h north for 750 miles. what is the average speed for the tri
iren2701 [21]
<span>Th find the average speed of a trip we need to dived the total distance by the total time. Let's find the total distance d. d = (300 mi/h)(2.00 h) + 750 miles d = 600 miles + 750 miles d = 1350 miles The total distance is 1350 miles Let's find the total time t. t = 2.00 hours + (750 mi / 250 mi/h) t = 2.00 hours + 3.00 hours t = 5.00 hours The total time of the trip is 5.00 hours. We can find the average speed. d / t = 1350 miles / 5.00 hours d / t = 270 miles/ hour The average speed of the trip is 270 mi/h (Note that the direction does not matter when we find the average speed.)</span>
6 0
4 years ago
A very long straight current-carrying wire produces a magnetic field of 25 µT at a distance d from the wire. How far will the ma
daser333 [38]

The magnetic field strength of a very long current-carrying wire is proportional to the inverse of the distance from the wire. The farther you go from the wire, the weaker the magnetic field becomes.

B ∝ 1/d

B = magnetic field strength, d = distance from wire

Calculate the scaling factor for d required to change B from 25μT to 2.8μT:

2.8μT/25μT = 1/k

k = 8.9

You must go to a distance of 8.9d to observe a magnetic field strength of 2.8μT

6 0
3 years ago
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