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madreJ [45]
3 years ago
6

I have no idea so i'm screwed please help me

Physics
1 answer:
podryga [215]3 years ago
8 0

Answer:

Let N0 be the initial atoms of Be11

N0 / 2^1 = N0 / 2  Number of Be11 after 1 half-life

N0 / 2^2 = N0/ 4   Number of Be11 after 2 half-lives

30/13.81 = 2.17 half lives

N0 / 2^2.17 = N0 / 4.51 = .222 N0 or 22.2 % of atoms remain

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Option C Magnetic force
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Convert the following to relative uncertainties <br>a) 2.70 ± 0.05cm<br>b) 12.02 ± 0.08cm
DENIUS [597]

data which is expressed in form of following way

a = a_o + \Delta a

here in above expression

a_o = true value

\Delta a = uncertainty in the value

now the relative uncertainty is given as

\frac{\Delta a}{a_o}

now by above formula we can say

a) 2.70 ± 0.05cm

here

True value = 2.70

uncertainty = 0.05

Relative uncertainty = \frac{0.05}{2.70} = 0.0185

b) 12.02 ± 0.08cm

here

True value = 12.02

uncertainty = 0.08

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4 0
3 years ago
Electrical energy is used to turn the blades of a fan. The amount of energy transformed is seen here: 750 j electrical energy is
MAVERICK [17]

Here is the energy that is left after the quantity of energy is transformed: 750 j of electrical energy is changed into 400 j of kinetic or mechanical energy, which is then turned into 0.32 j of efficient energy.

To run the fan, electrical energy is utilized.

Here, under the specified circumstances, 750 J of electrical energy is utilized to operate the fan, which is transformed into 400 J of kinetic energy. As a result, 350 J of energy is wasted due to various frictional and resistive losses.

Therefore, we may conclude that only 400 J of the 750 J available energy is used to power the fan, with the remaining energy being wasted as a result of friction.

Additionally, we can state that this fan's effectiveness will be

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4 0
1 year ago
A research submarine has a 20-cm-diameter window that is 9.0 cm thick. The manufacturer says the window can withstand forces up
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Answer:

The maximum safe depth in salt water is 3758.2 m.

Explanation:

Given that,

Diameter = 20 cm

Radius = 10 cm

Thickness = 9.0 cm

Force F = 1.2\times10^{6}\ N

Inside pressure = 1.0 atm

We need to calculate the area

Using formula of area

A=\pi\times r^2

Put the value into the formula

A=\pi\times(10\times10^{-2})^2

A=0.0314\ m^2

We need to calculate the pressure

Using formula of pressure

P=\dfrac{F}{A}

Put the value into the formula

P=\dfrac{1.2\times10^{6}}{0.0314}

P=38216560.50\ Pa

P=3.8\times10^{7}\ Pa

We need to calculate the maximum depth

Using equation of pressure

P=P_{atm}+\rho gh

h=\dfrac{P-P_{atm}}{\rho g}

Put the value into the formula

h=\dfrac{3.8\times10^{7}-101325}{1029\times9.8}

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Hence, The maximum safe depth in salt water is 3758.2 m.

4 0
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A rifle fires a bullet into a giant slab of butter on a frictionless surface. The bullet penetrates the butter, but while passin
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Answer:

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