Answer:
C) is zero
Explanation:
According to the law of energy conservation, the total mechanical energy of the object is conserved. A book falling a distance d would have a change in potential energy, resulting in the same change in kinetic energy. But the total mechanical energy must be the same. So there's 0 change in total energy of the system.
Answer:


Explanation:
Wave 1, 
Wave 2, 
Wave 3, 
Wave 4, 
The general equation of travelling wave is given by :

The value of
will remain the same if we take phase difference into account.
For first wave,



For second wave,



For the third wave,



For the fourth wave,



It is clear from above calculations that waves 1 and 3 have same time period. Also, wave 2 and 4 have same time period. Hence, this is the required solution.
B. Move from their ground states up to excited states
:)
Answer:
The correct answer is C.
Clarify any confusing information in the instructions.
Explanation:
The very first thing that we need before conducting a scientific investigation is a set of instructions which might include the following information:
-What we are experimenting on?
-How are we going to do it?
-What things are needed for it?
If there are any confusions in the instructions, the chances of making a mistake rises. So, it is very important to clarify the confusions found in the instructions before choosing things needed for the experiment and starting the experiment.
B) the crust is much thinner from the other layers