A sample of polonium-210 was left for 414 days.
BA
After this time it had a mass of 1.45 x 10^-4 g
The half-life of polonium-210 is 138 days.
Calculate the initial mass of the sample

Answers

Answer 1

Answer:

PO(1) = PO(0) / 2       1 refers to 1 half life of PO(0)

PO(2) = PO(1) / 2 = P(0) / 4        amount of PO left after 2 half-lives

PO(3) = PO(2) / 2 = PO(0) / 8     amount of PO left after 3 half-lives

414 da / 138 da = 3       3 half-lives pass in 414 da

PO(0) = 8 PO(3) = 8 * 1.45E-4 g = 1.16E-3 g = .00116 g  after 414 days        


Related Questions

If you took a balloon of gas and then warmed the balloon in a sunny window, what can now be said about the density of the gas in the balloon

Answers

Explanation:

The density of the gas in the balloon will explode

A 100 kg roller coaster comes over the first hill at 2 m/sec (vo). The height of the first hill (h) is 20 meters. See roller diagram below.

1) Find the total energy for the roller coaster at the initial point.

2) Find the potential energy at point A using the PE formula.

3) Use the conservation of energy to find the kinetic energy (KE) at point B.

4) Find the potential energy at point C.

5) Use the conservation of energy to find the Kinetic Energy (KE) of the roller coaster at point C.

6) Use the Kinetic Energy from C, find velocity of the roller coaster at point C.

Answers

For the 100 kg roller coaster that comes over the first hill of height 20 meters at 2 m/s, we have:

1) The total energy for the roller coaster at the initial point is 19820 J

2) The potential energy at point A is 19620 J

3) The kinetic energy at point B is 10010 J

4) The potential energy at point C is zero

5) The kinetic energy at point C is 19820 J

6) The velocity of the roller coaster at point C is 19.91 m/s

1) The total energy for the roller coaster at the initial point can be found as follows:

[tex] E_{t} = KE_{i} + PE_{i} [/tex]

Where:

KE: is the kinetic energy = (1/2)mv₀²

m: is the mass of the roller coaster = 100 kg

v₀: is the initial velocity = 2 m/s

PE: is the potential energy = mgh

g: is the acceleration due to gravity = 9.81 m/s²

h: is the height = 20 m

The total energy is:

[tex] E_{t} = KE_{i} + PE_{i} = \frac{1}{2}mv_{0}^{2} + mgh = \frac{1}{2}*100 kg*(2 m/s)^{2} + 100 kg*9.81 m/s^{2}*20 m = 19820 J [/tex]

Hence, the total energy for the roller coaster at the initial point is 19820 J.

   

2) The potential energy at point A is:

[tex] PE_{A} = mgh_{A} = 100 kg*9.81 m/s^{2}*20 m = 19620 J [/tex]

Then, the potential energy at point A is 19620 J.

3) The kinetic energy at point B is the following:

[tex] KE_{A} + PE_{A} = KE_{B} + PE_{B} [/tex]

[tex] KE_{B} = KE_{A} + PE_{A} - PE_{B} [/tex]

Since

[tex] KE_{A} + PE_{A} = KE_{i} + PE_{i} [/tex]

we have:

[tex] KE_{B} = KE_{i} + PE_{i} - PE_{B} =  19820 J - mgh_{B} = 19820 J - 100kg*9.81m/s^{2}*10 m = 10010 J [/tex]

Hence, the kinetic energy at point B is 10010 J.

4) The potential energy at point C is zero because h = 0 meters.

[tex] PE_{C} = mgh = 100 kg*9.81 m/s^{2}*0 m = 0 J [/tex]

5) The kinetic energy of the roller coaster at point C is:

[tex] KE_{i} + PE_{i} = KE_{C} + PE_{C} [/tex]            

[tex] KE_{C} = KE_{i} + PE_{i} = 19820 J [/tex]      

Therefore, the kinetic energy at point C is 19820 J.

6) The velocity of the roller coaster at point C is given by:

[tex] KE_{C} = \frac{1}{2}mv_{C}^{2} [/tex]

[tex] v_{C} = \sqrt{\frac{2KE_{C}}{m}} = \sqrt{\frac{2*19820 J}{100 kg}} = 19.91 m/s [/tex]

Hence, the velocity of the roller coaster at point C is 19.91 m/s.

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An object has an acceleration of 12.0 m/s/s. If the NetForce was tripled and the mass was doubled, then the new acceleration would be _____ m/s/s

Answers

Answer: that would be New acceleration would be 12 m/s²

Explanation:

Julie blows a bubble. At first, the pressure of the gas in the bubble is 4kPa. The bubble floats into the air and expands. When it gets to the top of a tree the bubble has a pressure of 2kPa and a volume of 3.5m³. Assuming a constant temperature, what was the volume in m³ of the bubble when it was first blown? Give your answer to three significant figures.

Answers

Answer:

P V = N R T

P1 V1 = P2 V2      assuming N, R, and T remain constant

V1 = (P2 / P1) V2

V1 = (2 kPa / 4 k Pa) 3.5 m3

V1 = 3.5 m^3 / 2 = 1.75 m^3

More potential energy can be stored by moving against the magnetic force closer to a magnet?

Answers

Answer:

if your saying can it? then yes or if you are asking what type of magnetic force  then its fr its actual self magnetic force

Explanation:

Is s=[tex]\frac{Ft^{2} }{2m}[/tex] a correct conversion from a=[tex]\frac{at^{2} }{2}[/tex]?

I just substituted "a" as [tex]\frac{F}{m}[/tex]

Answers

Answer:

well your substitution method is correct but make sure to double check the original formula

Josh and jake are both helping to build a brick wall which is 6 meters in height. They each lay 250 bricks, but josh finishes this task in 3 hours while jake requires 4.5 hours to complete his part. Who does more work, or do they both do the same amounth? Who has more power? Explain.

Answers

Each laid 250 bricks but while Jake was
still working, Josh was lounging in the
shade. Josh has more power but that
power was only on for 3 hours out of 4.5.
Obviously Josh could get more done is less
time as long as he keeps working. Jake will
get the hang of it soon.

eleven wa=eighs 47 kg. her height is 1.63 m. what is her bmi

Answers

Answer:

17.7kg/[tex]m^{2}[/tex]

Explanation:

                       BMI =

                             =  [tex]\frac{weight (kg)}{height (m) . height (m)}[/tex]

                             = 47kg/(1.63m×1.63m)

                             = 17.689kg/[tex]m^{2}[/tex]

                             ≈ 17.7kg/[tex]m^{2}[/tex]

what makes us think that the star system cygnus x-1 contains a black hole?

Answers

Answer:

Explanation:

What makes us think that the star system Cygnus X-1 contains a black hole? It emits X-rays characteristic of an accretion disk, but the unseen star in the system is too massive to be a neutron star.

The time (t) required to empty a tank varies inversely as the rate (r) of pumping. If a
pump can empty a tank in 3 hours at a rate of 400 gallons per minute, how long will it
take to empty a tank at 600 gallons per minute?

Answers

Answer:

T = C / R      t = time, C =constant of proportionality, R = rate

180 min = C / 400 gal/min      

C = 72000 gal      to empty tank

T = 72000 gal / 600 gal/min = 120 min = 2 hrs

Define power and explain how to determine power. (4 points)

Answers

The definition of power is operating electrically or having strength or force. An example of power is the functioning of a gasoline-driven saw or tool. Or Power is related to other quantities; for example, the power involved in moving a ground vehicle is the product of the traction force on the wheels and the velocity of the vehicle. The output power of a motor is the product of the torque that the motor generates and the angular velocity of its output shaft. Likewise, the power dissipated in an electrical element of a circuit is the product of the current flowing through the element and of the voltage across the element.

Sachi wants to throw a water balloon to knock over a target and win a prize. The target will only fall over if it is hit with a force of 0. 035 N. The water balloon has a mass of 11. 4 grams. How fast will Sachi have to make the water balloon accelerate to hit the target with enough force and win the prize? Round the answer to the nearest one tenth m/s2. The water balloon must accelerate m/s2.

Answers

Hi there!

We can use the following equation (Newton's Second Law):

∑F = ma

m = mass of object (kg)

a = acceleration (m/s²)

We can rearrange to solve for 'a':

F/m = a

Remember to convert grams to kg.

1000g = 1 kg

0.035/(0.0114) = 3.07 m/s²

An object with a mass of 90 grams, moving at a constant velocity of 6 meters per second, has __________. A. A momentum of 540 gram meters per second B. An acceleration of 10 meters per second squared C. A momentum of 90 gram meters per second D. An acceleration of 6 meters per second squared Please select the best answer from the choices provided. A B C D.

Answers

Answer: 540 g m/s.

Explanation:

Answer: A.

A momentum of 540 gram meters per second!

Explanation: On Edge!!

What do you mean by 100w power?​

Answers

If you have a Light bulb that has a rating of 100 watt, it means that the light bulb consumes 100 J per second. kWh is the unit of energy. You can compare this to the volume of water that comes out of the pipe. A 100 watt light bulb when used for an hour will consume 100 Watt-hour of energy which is 0.1 kWh of energy.

why the max Static frictional force is a Little bit bigger than the sliding frictional force​

Answers

Static Friction is more than sliding friction because, in case of STATIC FRICTION, the body needs to overcome the inertia of rest. And also in case of SLIDING FRICTION, the body posses inertia of motion since the body is already in motion.

Hope it helps!

during which lunar phase does every solar eclipse occur?

Answers

Answer:

It has to be the "New Moon" because that is when the moon is between the sun and the earth.

A lunar eclipse can occur when the earth is between the sun and the moon.

Which statement indicates that motion has occurred?

A. The reference point has changed.

B. The position of the object has changed.

C.The object has not changed.

D. The object being described has changed​

Answers

The answer is b i think

An object's _____ energy that is used to perform work is equal to its potential energy plus its kinetic energy.

Answers

its the British government

Which of the following is a defense technique to protect computers from incoming risks? *

Answers

Answer:

having a secure firewall

Explanation:

A firewall validates access by assessing this incoming traffic for any price malicious like hackers and malware that would infect your computer.

plz help, dont need to do the last question

Answers

Answer:

Explanation:

I dont understand what its saying .....?

There are no risks when taking medication to treat anxiety.


Please select the best answer from the choices provided.

T
F

Answers

Answer:

False

Explanation:

Answer:

The answer is False

Explanation:

Which of the following substances cannot be broken down into simpler substances?
Table Salt (NaCl)
Water (Hsub2O)

Sand (SiOsub2)
Potassium (K)

Answers

Potassium because it is an element and not a compound

Name some devices we use to make measurements

Answers

Answer:

Explanation:

Ruler. A steel ruler aids the measurement and layout of straight lines. The ruler, also called "straightedge" or "straight-edged ruler," is a long, thin strip of wood, metal or plastic marked with increments of measurement.

Measuring Tape. The modern measuring tape's roughly palm-sized casing contains a coiled strip of metal marked with increments of measurement. The metal strip, called "tape," attaches to a spring which automatically retracts the tape into the casing following use.

Walking Tape Measure. The walking tape measure, also called "surveyor's measure," records the distance traveled by a wheel. An operator pushes the measure's wheel, similar to a bicycle wheel, by a handle as an attached ticker box displays feet or meters in the same format as a car's odometer.

Laser Measure. The laser measure offers point and shoot distance measurement. In its most basic form, a laser measure is a hand-held electronic device with a digital display.

3. What happens if an object has a negative acceleration?​

Answers

Answer:

They will go backwards?

Explanation:

If positive they go forward but is negative they go backwards.

Which object has the most thermal energy?
A. A 6 kg rock at 10°C
B. A 10 kg rock at 10°C
C. A6 kg rock at 15°C
D. A 10 kg rock at 15°C

Answers

Answer:

D is the answer

Explanation:

D is the most highest one so

the answer is D

Answer:

10 kg rock at 15 degrees celcius

your field of study in college is called your________.

Answers

Answer:

Majors are also called concentrations. An academic major or concentration is a college or university student's main field of specialization during his or her associates or undergraduate studies which would be in addition to, and may incorporate portions of, a core curriculum.

What can cause matter to change from one state to another?

a change in its temperature

a change in its pressure

both a and b

neither a nor b

Answers

The answer is Both A and B

The spark plugs are threaded into the top of each cylinder and provide a place for the spark to jump within the ________.

Answers

Answer:

"the spark plug gap"

The plug provides a gap between the input voltage and the ground supplied by the car chassis.

PLEASE PLEASE PLEASE HELP ME!!!

Answers

Answer: Levers

Explanation: Levers lifte

the machines arm

______is the rate of change of velocity. A,speed. B,distance. C,acceleration. D,force​

Answers

It is C Acceleration

Explanation:

c) aceleración

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