Answer:
the only one of these materials that allows studying processes of a very long period of time is Uranium 238
Explanation:
In a radioactive material, half of the atoms decay each life period, in carbon 14 this period T = 5730 years, so for a time of 40,000 years there are 7 life periods, so there are very few atoms left without decomposing .
To study older samples, materials with a longer life period are needed, let's show the visa time
²³⁸U T= 4.5 10¹⁰ years
⁹¹Rb T = 58 s
¹³¹I T= 8.04 days
⁶⁰Co T= 5.27 years
Therefore, the only one of these materials that allows studying processes of a very long period of time is Uranium 238
Answer: The statement when the motion energy of an object changes, energy is being transferred is true.
Explanation:
Motion energy is also called mechanical energy and it is the summation of kinetic energy and potential energy stored in an object required for work.
As kinetic energy is the energy acquired due to motion of an object and potential energy is the energy acquired by an object due to its position.
For example, when a moving ball strikes another ball causing it to move then energy is being transferred from one ball to another.
Therefore, the statement when the motion energy of an object changes, energy is being transferred is true.
Answer & Explanation:
One can pick up a nail using the curved part of the horseshoe magnet farthest from the poles. A horse shoe magnet has magnetic fields all around it. In the presence of magnetic force fields, any magnetic object will be attracted to it.