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stealth61 [152]
3 years ago
5

Francium-223 has a half-life of 22 minutes. A Geiger counter gives a reading of 58 counts per minute (cpm) from a sample of fran

cium-223. What will the reading be 22 minutes later? You can ignore background radiation.
Physics
1 answer:
polet [3.4K]3 years ago
8 0

Answer:

29 counts per minute (29 cpm)

Explanation:

The half-life of a radioactive isotope is the time needed for the activity of the sample to halve.The half-life of Francium-223 is exactly 22 minutes: this means that its activity after 22 minutes becomes exactly half of its initial value. Since the initial activity of this sample of francium-223 was 58 cpm, the activity after 22 minutes will be

A=\frac{58 cpm}{2}=29 cpm

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Examine the images of the Grand Canyon below. Notice that most of the canyon consists of layers of sedimentary rocks, but if you
Tomtit [17]

Intense temperature and pressure of regional metamorphism

Explanation:

The process that cause the formation of the Vishnu Schist is the intense temperature and pressure as a result of regional metamorphism.

  • Regional metamorphism is an extensive metamorphism of an area as a result of temperature and pressure changes.
  • The schist is a foliated metamorphic rock usually found in areas of moderate to high grade temperature and pressure.
  • The Vishnu schist must have been metamorphosed before the new sediments were deposited on top.

Learn more:

Contact metamorphism brainly.com/question/1970623

#learnwithBrainly

7 0
3 years ago
a hunter 412.5m from a cliff moves a distance x towards the cliff and fires a gun. he hears the echo from the cliff after 2.2sec
Inessa [10]

Answer: 49.5 m

Explanation:

The speed of sound s is given by a relation between the distance d and the time t:

s=\frac{d}{t} (1)

Where:

s=330 m/s is the speed of sound in air (taking into account this value may vary according to the medium the sound wave travels)

d=412.5 m-x since we are told th hunter was initially 412.5 meters from the cliff and then moves a distance x towards the cliff

t=\frac{2.2 s}{2}=1.1 s Since the time given as data (2.2 s) is the time it takes to the sound wave to travel from the hunter's gun and then go back to the position where the hunter is after being reflected by the cliff

Having this information clarified, let's isolate d and then find x:

d=st (2)

412.5 m-x=(330 m/s)(1.1 s) (3)

Finding x:

x=49.5 m This is the distance at which the hunter is from the cliff.

3 0
3 years ago
What is the least force you could exert on the refrigerator to move it?
Ulleksa [173]
 <span>If the refrigerator weights 1365 and you are not exerting any vertical force on it, then the normal force is also 1365N. so Fn=1365 

Fsf = Static frictional force = (coefficient of static friction) * (Normal force) 

So the least for you could exert to move it is equal to the Fsf. 
Fsf = (0.49)(1365N)</span><span>
</span>
8 0
3 years ago
Consider the following FBDs.FBDsAn elevator is suspended by a cable and moves uniformly upward. Which of the above free body dia
Drupady [299]

The force of gravity F_g will act downwards.

Normal force F_N will act upwards equal to the force of gravity.

A force due to uniform acceleration F_a will act upwards to move the elevator upwards.

Thus, figure E is the correct answer.

6 0
1 year ago
Two planets, Dean and Sam, orbit the Sun. They each have with circular orbits, but orbit at different distances from the Sun. De
lyudmila [28]

Answer:

The correct answer is Dean has a period greater than San

Explanation:

Kepler's third law is an application of Newton's second law where the force is the universal force of attraction for circular orbits, where it is obtained.

                T² = (4π² / G M)  r³

When applying this equation to our case, the planet with a greater orbit must have a greater period.

Consequently Dean must have a period greater than San which has the smallest orbit

The correct answer is Dean has a period greater than San

3 0
3 years ago
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