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1 year ago

A student weighs a sample of an unkown metal and finds the mass to be 39.27g what is the metal?

Physics

1 answer:

xxTIMURxx [149]1 year ago

7 0

The unknown metal with a mass of 39.27 g is potassium with the symbol K.

The mass of an atom is due to protons and neutrons present in it.

The protons and neutrons are together present in the nucleus of an atom.

The mass of any element is given by its mass number whose formula is

Mass Number = Number of protons + Number of neutrons

In the given case 39 = Number of protons + Number of neutrons

The only element of the periodic table which satisfies the above equation is potassium because it has 19 protons and 20 neutrons.

Thus, the unknown metal with a mass of 39.27 g is potassium with the symbol K.

To know more about "mass number", refer to the following link:

brainly.com/question/4408975?referrer=searchResults

#SPJ4

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Lithium has 3 protons. how many neutrons are in the isotope lithium -8

Oksi-84 [34.3K]

Answer:

5 neutrons

Explanation:

Both protons and neutrons have a mass of about 1 atomic mass unit (amu). The number in the notation for an isotope is its mass in amu. That means the number is essentially the sum of protons and neutrons in the isotope (electrons don't contribute significantly to the mass).

If lithium has 3 protons, lithium-8 has 8 - 3 = 5 neutrons.

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2 years ago

Read 2 more answers

Course hero N4M.6 A board has one end wedged under a rock having a mass of 380 kg and is supported by another rock that touches

aleksandrvk [35]

Answer:

Therefore it is save to carry a 62kg adult

Explanation:

From the question we are told that:

Mass $m=380kg$

Height of supporting Rock $X=85cm$

Length of Board $L_r=4.5m$

Mass of board $M_b=22kg$

Mass of adult $M_a=62$

Generally the moment of balance about wedge part about is mathematically given by

$N -Q + R = Mg + mg$

$0.85*N - Mg*2.25 - mg*(2.25 + x) = 0$

$0.85*N = + Mg*2.25 + mg*(2.25 + x)$

where

$N+R=4547$

therefore

$N = 570.70588 + 1608.3529 + 714.823 x$

if N=0 at fallen person

$x=3.04m$

Therefore it is save to carry a 62kg adult

8 0

2 years ago

Can somebody help me with this quiz please

mezya [45]

Sure what do u need help with

4 0

2 years ago

Air "breaks down" when the electric field strength reaches 3×106n/c, causing a spark. a parallel-plate capacitor is made from tw

aalyn [17]

Ok, I think this is right but I am not sure:
Q = ϵ
0AE
A= π π
r^2

=(8.85x10^-12 C^2/Nm^2)
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2 years ago

If the value of static friction for a couch is 400N, what could be a possible value of its kinetic friction? *

Dafna11 [192]

Answer:

kinetic friction may be greater than 400 N or smaller than 400 N

Explanation:

As we know that maximum value of static friction on the rough surface is known as limiting friction and the formula of this limiting friction is known as

$F_s = \mu_s N$

now when object is sliding on the rough surface then the friction force on that surface is known as kinetic friction and the formula of kinetic friction is known as

$F_k = \mu_k N$

now we know that

$\mu_k < \mu_s$

so here value of limiting static friction force is always more than kinetic friction

also we know that

initially when body is at rest then static friction value will lie from 0 N to maximum limiting friction

and hence kinetic friction may be greater than static friction or if the static friction is maximum limiting friction then kinetic friction is smaller than static friction

so kinetic friction may be greater than 400 N or smaller than 400 N

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3 years ago