Explanation:
Nuclear reactions are the reactions in which nucleus of an atom changes either by splitting or joining with the nucleus of another atom.
There are two types of nuclear reactions.
- Nuclear fission - In this process, large atomic nuclei splits into smaller nuclei.
- Nuclear fusion - In this process, two small nuclei combine together to form a large nuclei.
Both nuclear fission and fusion processes involve nuclei of atoms.
For example, 
Thus, we can conclude that statements which are true are as follows.
- Nuclear reactions involve the nuclei of atoms.
- The products of nuclear reactions are lighter than the reactants.
Answer:
Explanation:
The energy of Mass-Spring System the sum of the potential energy of the block plus the kinetic energy of the block:
Where:
There are two cases, the first case is when the spring is compressed to its maximum value, in this case the value of the kinetic energy is zero, since there is no speed, so:
The second case is when the block passes through its equilibrium position, in this case the elastic potential energy is zero since 
, so:
Now, let's find the energy of the system when the block is replaced by one whose mass is twice the mass of the original block using the previous data:
Where in this case:
Therefore:
Answer:
R = 6.8
Explanation:
Given data:
Richter scale
where R - magnitude of earthquake of Richter scale
I - quake's intensity 
- minimum intensity earthquake
Plugging all information in the equation to get Richter's scale
R = 6.8
Each time a uranium nucleus splits<span> up it releases energy and three neutrons. If all the neutrons are allowed to be absorbed by other uranium nuclei the chain reaction will spiral out of control causing an explosion. To control the energy released in the reactor moveable control rods are placed between the fuel rods.</span>
Answer: a) 1.6 * 10 ^-7 N/C (upward) ; b) -2.5*10^-6N (downward)
Explanation: In order to solve this proble we have to use the Coulomb law given by:
F=q*E from this expression we have
E=F/q=4.8*10^-6/30 C= 1.6 * 10 ^-7 N/C
The force on the particle charge by -1.6 X10 C place intead of the initial charge we have
F=q*E= -16 C* 1.6 * 10 ^-7 N/C= -2.5*10^-6N
