Answer:
Option B, Some of the cars' kinetic energy was converted to sound and heat energy.
Explanation:
In an elastic collision, no energy is lost during and after collision. Thus, it can be said that in an elastic collision both momentum and kinetic energy remains conserved.
While in non-elastic collision, kinetic energy of the system is lost. However, the momentum of the system is conserved. Generally, during and after collision some of the kinetic energy is lost as thermal energy, sound energy etc.
Hence, option B is correct
Answer:
0
Explanation:
because during free fall we experience wieghtlessness
Answer:
Hydroelectricity is a renewable energy source.
Hydroelectricity increases the stability and reliability of electricity system
Hydroelectricity helps fight climate changes.
Explanation:
If we use hydroelectricity our country would be in good climate and not a bad one. And the best facts it is renewable.
I'm not sure about the rest but for question 2:
A theory is an attempt to come up with a big picture of all we know so far. It also drives future research as people do experiments to see if what the theory predicts actually happens. When experiments don’t support the theory, you have to change the theory and try again. That’s how science works. We come up with a “best guess” (theory), and then do research to test it’s accuracy. As we discover contradictions, we adjust the theory to take those into account, and then start testing the validity of the new theory.
Answer:
a. 240 N due east
b. 540 N due west
Explanation:
Let east be the reference direction
(a) if the resultant force has a magnitude of 390 N and points east, and the 1st force is 150N due East, then the additional force would also due east and has a magnitude of
390 - 150 = 240 N
(b) if the resultant force has a magnitude of 390 N and points west, it would be -390N is eastern reference, and the 1st force is 150N due East, then the additional force would also due east and has a magnitude of
-390 - 150 = -540 N
This force would point west