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2 years ago

10

The atomic number of yttrium is 39. The atomic mass of one of its isotopes is 89. How many neutrons are in an atom of this isoto

pe?

1 answer:

gogolik [260]2 years ago

8 0

50. The atomic mass is essentially a tally of all of the atoms in the nucleus, since electrons are essentially negligible in mass.

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What happens during destructive interference?

Masteriza [31]

They will subtract to form a combined wave with a lower amplitude

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3 years ago

A student claims "everything falls at the same acceleration rate on the Moon, where there is no air or friction," how would you

Alexeev081 [22]

Now let’s say you’re on the Moon. If you were to drop a hammer and a feather from the same height, which would hit the ground first?

Trick Question! On the moon both objects would hit the ground at the same time. On Earth, the hammer lands first.

So yeah, the student is right. Galileo gave us this theory long ago.

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2 years ago

A 120 g, 8.0-cm-diameter gyroscope is spun at 1000 rpm and allowed to precess. What is the precession period?

dolphi86 [110]

To solve this problem we will derive the expression of the precession period from the moment of inertia of the given object. We will convert the units that are not in SI, and finally we will find the precession period with the variables found. Let's start defining the moment of inertia.

$I = MR^2$

Here,

M = Mass

R = Radius of the hoop

The precession frequency is given as

$\Omega = \frac{Mgd}{I\omega}$

Here,

M = Mass

g= Acceleration due to gravity

d = Distance of center of mass from pivot

I = Moment of inertia

$\omega$ = Angular velocity

Replacing the value for moment of inertia

$\Omega= \frac{MgR}{MR^2 \omega}$

$\Omega = \frac{g}{R\omega}$

The value for our angular velocity is not in SI, then

$\omega = 1000rpm (\frac{2\pi rad}{1 rev})(\frac{1min}{60s})$

$\omega = 104.7rad/s$

Replacing our values we have that

$\Omega = \frac{9.8m/s^2}{(8*10^{-2}m)(104.7rad)}$

$\Omega = 1.17rad/s$

The precession frequency is

$\Omega = \frac{2\pi rad}{T}$

$T = \frac{2\pi rad}{\Omega}$

$T = \frac{2\pi}{1.17}$

$T = 5.4 s$

Therefore the precession period is 5.4s

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2 years ago

Help Meeee Please!!!!! This was due so long ago... DO NOT REPORT, THERE IS NO REASON TO REPORT! Assignment: Weathering in Action

zaharov [31]

Answer: Chemical

Explanation: because it is changeing its chemical structure if its wrong sorry .

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3 years ago

What the exercise or play in the p.e in the philippines?<br> please!!!!, please!!!!

Debora [2.8K]

Answer:

They could be jumping off structures, running or climbing on rocks. They also could be participating in sports like soccer.

Explanation:

sources:

https://www.philippinesbasiceducation.us/2013/06/physical-activity-and-physical.html - about there play schedule

http://sportphil.com/category/articles/ - concil of philippines

Sorry that's all I could find.

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2 years ago

Read 2 more answers