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3 years ago

A copper part is heated. Does its mass, volume and density change?

Physics

2 answers:

DENIUS [597]3 years ago

6 0

Answer:

It's volume and density will increase but NOT the mass

Explanation:

Heating copper in its elemental form is a physical change.

The mass of any substance does not change during a physical change, so the mass of copper will stay the same. However, its volume will increase, so its density will decrease.

shusha [124]3 years ago

3 0

Answer:

Heating copper in its elemental form is a physical change. The mass of any substance does not change during a physical change, so the mass of copper will stay the same. However, its volume will increase, so its density will decrease

Explanation:

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How much work is done (by a battery, generator, or some other source of potential difference) in moving Avogadro's number of ele

konstantin123 [22]

Answer:

-1486 KJ

Explanation:

The work done by an electric field on a charged body is:

W = ΔV * q

where ΔV = change in voltage

q = total charge

The total charge of Avogadro's number of electrons is:

6.0221409 * 10^(23) * -1.6023 * 10^(-19) = -9.65 * 10^(4)

The change in voltage, ΔV, is:

9.20 - (6.90) = 15.4

Therefore, the work done is:

W = -9.65 * 10^(4) * 15.4 = -1.486 * 10^6 J = -1486 KJ

The negative sign means that the motion of the electrons is opposite the electrostatic force.

5 0

3 years ago

Potassium is a crucial element for the healthy operation of the human body. Potassium occurs naturally in our environment and th

gregori [183]

Complete Question

Potassium is a crucial element for the healthy operation of the human body. Potassium occurs naturally in our environment and thus our bodies) as three isotopes: Potassium-39, Potassium-40, and Potassium-41. Their current abundances are 93.26%, 0.012% and 6.728%. A typical human body contains about 3.0 grams of Potassium per kilogram of body mass. 1. How much Potassium-40 is present in a person with a mass of 80 kg? 2. If, on average, the decay of Potassium-40 results in 1.10 MeV of energy absorbed, determine the effective dose (in Sieverts) per year due to Potassium-40 in an 80- kg body. Assume an RBE of 1.2. The half-life of Potassium-40 is $1.28 * 10^9$ years.

Answer:

The potassium-40 present in 80 kg is $Z = 0.0288 *10^{-3}\ kg$

The effective dose absorbed per year is $x = 2.06 *10^{-24}$ per year

Explanation:

From the question we are told that

The mass of potassium in 1 kg of human body is $m = 3g= \frac{3}{1000} = 3*10^{-3} \ kg$

The mass of the person is $M = 80 \ kg$

The abundance of Potassium-39 is 93.26%

The abundance of Potassium-40 is 0.012%

The abundance of Potassium-41 is 6.78 %

The energy absorbed is $E = 1.10MeV = 1.10 *10^{6} * 1.602 *10^{-19} = 1.7622*10^{-13} J$

Now 1 kg of human body contains $3.0*10^{-3}\ kg$ of Potassium

So 80 kg of human body contains k kg of Potassium

=> $k = \frac{ 80 * 3*10^{-3}}{1}$

$k = 0.240\ kg$

Now from the question potassium-40 is 0.012% of the total potassium so

Amount of potassium-40 present is mathematically represented as

$Z = \frac{0.012}{100} * 0.240$

$Z = 0.0288 *10^{-3}\ kg$

The effective dose (in Sieverts) per year due to Potassium-40 in an 80- kg body is mathematically evaluated as

$D = \frac{E}{M}$

Substituting values

$D = \frac{1.7622*10^{-13}}{80}$

$D = 2.2*10^{-15} J/kg$

Converting to Sieverts

We have

$D_s = REB * D$

$D_s = 1.2 * 2.2 *10^{-15}$

$D_s = 2.64 *10^{-15}$

for half-life ( $1.28 *10^9 \ years$ ) the dose is $2.64 *10^{-15}$

Then for 1 year the dose would be x

=> $x = \frac{2.64 *10^{-15}}{1.28 * 10^9}$

$x = 2.06 *10^{-24}$ per year

7 0

3 years ago

A cart of mass 0.8 kg on a horizontal frictionless track has a tension of 4 N applied to on side of the cart. Calculate the acce

sweet [91]

Answer:

Option (c).

Explanation:

Given that,

Mass of a cart, m = 0.8 kg

Tension in the car, F = 4 N

Net force, F = ma

a is acceleration of the cart.

So,

$a=\dfrac{F}{m}\\\\a=\dfrac{4\ N}{0.8\ kg}\\\\a=5\ m/s^2$

So, the acceleration of the cart is $5\ m/s^2$ .

7 0

3 years ago

How many turns are in the secondary coil of a step up transformer that increases voltage from 30 V to 150 V and has seven turns

Mademuasel [1]

350 + 507 = 3657 that would be your answer

7 0

3 years ago

a fluid has a density of 921 kg/m^3. at a depth of 1.22 m, the fluid pressure is 122,000 Pa. what is the pressure at the top of

Zielflug [23.3K]

Answer:

Patm or the presion at the top is equal to 110977.28[Pa]

Explanation:

First we must define the absolute pressure value, which is equal to the sum of the atmospheric pressure plus the manometrial pressure.

$P_{abs} = P_{atm}+P_{man}\\where:\\P_{abs}=122000[Pa]$

Now we can find the manometric pressure.

$P_{man} = density*g*h\\where:\\density = 921[kg/m^3]\\g = gravity = 9.81[m/s^2]\\h = depth = 1.22[m]$

$P_{man} = 921*9.81*1.22\\ P_{man}= 11022.71[Pa]$

Therefore:

$P_{atm} = P_{abs} - P_{man} \\P_{atm} = 122000 - 11022.71\\P_{atm}= 110977.28[Pa]$

4 0

3 years ago