1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Anarel [89]
3 years ago
15

There is a 50 g sample of Ra-229. It has a half-life of 4 minutes.

Physics
1 answer:
Sloan [31]3 years ago
4 0

Via half-life equation we have:


A_{final}=A_{initial}(\frac{1}{2})^{\frac{t}{h} }


Where the initial amount is 50 grams, half-life is 4 minutes, and time elapsed is 12 minutes.  By plugging those values in we get:

A_{final}=50(\frac{1}{2})^\frac{12}{4}=50(\frac{1}{2})^{3}=50(\frac{1}{8})=6.25g


There is 6.25 grams left of Ra-229 after 12 minutes.

You might be interested in
1) A plane lands on a runway with a speed of 125 m/s, moving east, and it slows to a stop in 13.0 s. What is the magnitude (in m
valentina_108 [34]

Answer: 1) a = 9.61m/s² pointing to west.

             2) (a) Δv = - 37.9km/s

                  (b) a = - 6.10⁷km/years

Explanation: Aceleration is the change in velocity over change in time.

1) For the plane:

a=\frac{\Delta v}{\Delta t}

a=\frac{125}{13}

a = 9.61m/s²

The plane is moving east, so velocity points in that direction. However, it is stopping at the time of 13s, so acceleration's direction is in the opposite direction. Therefore, acceleration points towards west.

2) Total change of velocity:

\Delta v = v_{f}-v_{i}

\Delta v = -17.1-(+20.8)

\Delta v= -37.9km/s

The interval is in years, so transforming seconds in years:

v = \frac{-37.9}{3.15.10^{-7}}

v=-12.03.10^{7}km/years

Calculating acceleration:

a=\frac{-12.03.10^{-7}}{2.01}

a=-6.10^{7}

Acceleration of an asteroid is a = -6.10⁷km/years .

5 0
3 years ago
A crate of 45.2-kg tools rests on a horizontal floor. You exert a gradually increasing horizontal push on it and observe that th
iragen [17]

Answer:

 μ = 0.725

Explanation:

This problem refers to Newton's second law.

       F = ma

Let's write the equations on each axis

Y Axis

      N-W = 0

     N = W

    N = mg

X axis

   F-fr = ma

With the body not started moving its acceleration is zero

  F-fr = 0

  F = fr

The friction force equation is

  fr = μ N

  fr = μ m g

Let's replace and calculate

   F = μ m g

   μ = F / mg

   μ = 321 /45.2 9.8

   μ = 0.725

8 0
3 years ago
What is the law of variation of the period T of a simple pendulum
DIA [1.3K]
The period of a simple pendulum is given by:
T=2 \pi  \sqrt{ \frac{L}{g} }
where L is the length of the pendulum and g=9.81 m/s^2 is the gravitational acceleration. As we can see, the period of a simple pendulum depends only on its length.
3 0
3 years ago
To remove 700 j of heat from a refrigerator, the compressor in the refrigerator does 500 j of work. How much heat is released in
Vinvika [58]
If the compressor removes 500 j if the 700 the 200 j left would have Ben conducted through the refrigerator/200 j released into the room
7 0
3 years ago
What tempature does stone turn to lava?
rosijanka [135]
I would say 1000c as my answer
5 0
3 years ago
Other questions:
  • A reaction that absorbs 49.6 kj from the surroundings in a vessel that undergoes a volume decrease of 1.25 l at a constant 4.00
    8·2 answers
  • Why do bolt cutters have long handles and short blades laws of physics?
    6·1 answer
  • Please help me with this question, especially the angle part. I have solved the initial velocity already. I don't know what to d
    10·1 answer
  • 0/2 File Limit
    8·1 answer
  • Saul converts 2.392 hectoliters to liters. What should his new number be? 0.02392 0.2392 239.2 2392
    13·2 answers
  • A person's resting heart rate typically lessens<br> with age.
    6·2 answers
  • A certain lightning bolt moves 40.0 C of charge. How many fundamental units of charge |qe| is this?
    13·2 answers
  • A motorcycle (mass of cycle plus rider = 2x 10^2 kg) is traveling at a steady speed of 20 m/s.?The force of air resistance actin
    11·1 answer
  • What is the dimensional formula of young modulas​
    13·2 answers
  • a scientists collects a core sample from 60 km deep in earth what will she most likley observe plz help taking a test
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!