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liberstina [14]
3 years ago
5

A shield of material that reflects neutrons is placed around a radioactive sample.

Physics
2 answers:
Tanya [424]3 years ago
4 0
<h3><u>Answer;</u></h3>

A) A chain reaction will be sustained in a sub-critical mass

<h3><u>Explanation</u>;</h3>
  • Critical mass is the minimum or the smallest amount of a given fissile material necessary to achieve a self-sustaining fission chain reaction under stated conditions.
  • A subcritical mass is a mass of fissile material that does not have the ability to sustain a fission chain reaction.
nikitadnepr [17]3 years ago
3 0
The answer is A. just took the test
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You have been hired to design a spring-launched roller coaster that will carry two passengers per car. The car goes up a 12-m-hi
Vlada [557]

Answer:

Vmax=11.53 m/s

Explanation:

from conservation of energy

      E_A} =E_{B}

     Spring potential energy =potential energy due to elevation

   0.5*k*x²= mg(h_{B}-h_{A} )=mgh

   0.5*k*2.3²= 430*9.81*6

         k=9568.92 N/m

For safety reason

                                 k"=1.13 *k= 1.13*9568.92

                                    k"=10812.88 N/m

agsin from conservation of energy

      E_A} =E_{C}

    spring potential energy=change in kinetic energy

   0.5*k"*x²=0.5*m*V_{max}^{2}

      10812.88 *2.3²=430*V_{max}^{2}

           V_{max}=11.53 m/s

5 0
3 years ago
A ball is dropped from a rooftop 60m high. <br> How long is the ball in the air?
alina1380 [7]

Answer: 3.49 s

Explanation:

We can solve this problem with the following equation of motion:

y=y_{o}+V_{o}t-\frac{1}{2}gt^{2} (1)

Where:

y=0 m is the final height of the ball

y_{o}=60 m is the initial height of the ball

V_{o}=0 m/s is the initial velocity (the ball was dropped)

g=9.8 m/s^{2} is the acceleratio due gravity

t is the time

Isolating t:

t=\sqrt{\frac{2 y_{o}}{g}} (2)

t=\sqrt{\frac{2 (60 m)}{9.8 m/s^{2}}} (3)

Finally we find the time the ball is in the air:

t=3.49 s (4)

7 0
3 years ago
A penny rolls along the table for a distance of 1.3 meters. Jackie pushes it 40 centimeters further in the same direction.
brilliants [131]
40 meters times 1 meter over 100 centimeters equals 0.4 meters. 1.3 meters + 40 centimeters =. 1.3 m + 0.4 m = 1.7 m. The answer is 1.7 meters
7 0
3 years ago
Summarize the Venn diagram.
Elena L [17]

Answer:

If this is a multiple choice question, then the answer is D.

Explanation:

Compounds are composed of atoms, which are composed of subatomic particles and consist of matter. Since they are composed of atoms rather than vice-versa, compounds cannot be found inside atoms and are not the most basic form of matter (ruling out A and C). A pure substance contains atoms, which are each composed of subatomic particles. Therefore, a pure substance must have atoms if it contains subatomic particles (ruling out B). The only answer left is D.

5 0
3 years ago
What is the speed of sound in air when the temperature is 20°C?
Anarel [89]
The answer to your question is 343 m/s
5 0
3 years ago
Read 2 more answers
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