Answer:
m =8.81*10^{-6}grams
time t = 52.8 year
Explanation:
GIVEN DATA:
the half life of the CO-60 is, T_1/2 = 5.27 years = 1.663 e+8 s
activity dN/dt = 1 mCi = 3.7 X 10^7 decay/s
activity , 


= ( 3.7 X 10^7 )(1.663*10^8 ) / ln2
= 8.877*10^{16}
Number of moles:
n = N/NA = 8.877*10^{16} / 6.022X10^23 = 1.474*10^{-7} mol
mass of the CO-60 is,
m = n*M = [1.474*10^{-7} mol]*[59.93 grams /mol] = 8.81*10^{-6}grams
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time t = -[T1/2 / ln2]*ln[N/N0]
= - [5.3 years / ln2]*ln[1x10-6/1x10-3]
= 52.8 year
Newton's First Law states that an object will remain at rest or in uniform motion in a straight line unless acted upon by an external force.
<span>The tire will rotate about 10 million times.
An automobile tire is slightly less than 2 and half feet in diameter. It's circumference is that times pi with is a bit over 3. So 2.5 * 3 = 7.5 ft as an estimate for how far the tire rolls per revolution.
A mile is a bit over 5000 feet, so call it 700 revolutions per mile.
For the 35000 miles, call it 7 times 5000 miles. Now 7 times 7 is a bit under 50, so call 7 * 700 = 5000. And 5000 times 5000 = 25000000. The nearest order of magnitude is 10 million.
So as an order of magnitude estimate, a automobile tire will rotate about 10 million times during it's life.</span>
Answer:
a
The time it would take the beef to reach a temperature of 0⁰C is t= 662 sec = 11.93 min
b)
The time it would take to heat the beef to uniform temperature of 80⁰C is
t = 365 sec =5.93 min
c
Efficient absorption of Microwave power is in regions of liquid water . Hence if the food or the microwave irradiation is not uniform, the power will be absorbed non-uniformly, resulting in a non-uniform temperature rise. Defrost region will absorb more energy per unit volume than frozen region.if food is of low thermal conductivity, there will be insufficient time for heat conduction to make the temperature more uniform.Use of low power allows more time for conduction to occur.
Explanation:
The explanation is shown on the first second and third uploaded image