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svet-max [94.6K]

3 years ago

10

If a 4000 gram sample has a half-life of 1 million years and has 500 grams of radioactive parent isotope left how old is it

1 answer:

Arisa [49]3 years ago

4 0

3 million years

Happy to help

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An object is stopped at point ‘a’, and travels to point ‘c’ in 8s. What was its acceleration?

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In SI units, its acceleration is (the distance from A to C) / 32 m/s^2 .

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How can you show that pressure increases with the increase of force?

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Which states of matter are significantly compressible?

andreev551 [17]

Hello.

The gaseous state is the more compressible state, because it has the volume of its container.

The liquid state is virtually incompressible, and the solid state compression is very small.

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2 years ago

A mass weighting 16 lbs stretches a spring 3 inches. The mass is in a medium that exerts a viscous resistance of 20 lbs when the

const2013 [10]

Answer:

The equation for the object's displacement is $u(t)=0.583cos11.35t$

Explanation:

Given:

m = 16 lb

δ = 3 in

The stiffness is:

$k=\frac{m}{\delta } =\frac{16}{3} =5.33lb/in$

The angular speed is:

$w=\sqrt{\frac{k}{m} } =\sqrt{\frac{5.33*386.4}{16} } =11.35rad/s$

The damping force is:

$F_{D} =cu$

Where

FD = 20 lb

u = 4 ft/s = 48 in/s

Replacing:

$c=\frac{F_{D} }{u} =\frac{20}{48} =0.42lbs/in$

The critical damping is equal:

$c_{c} =\frac{2k}{w} =\frac{2*5.33}{11.35} =0.94lbs/in$

Like cc>c the system is undamped

The equilibrium expression is:

$u(t)=u(o)coswt+u'(o)sinwt\\u(o)=7=0.583\\u'(o)=0\\u(t)=0.583coswt\\u(t)=0.583cos11.35t$

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3 years ago

Which substance is uniquely a product of incomplete combustion of a fossil fuel?

Serga [27]

I can think of two of them:

-- carbon monoxide

-- black soot

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3 years ago