Disease
Lack of natural reourses
war
asteroid
Polution.
Answer:
emf will also be 10 times less as compared to when it has fallen 
Explanation:
We know, from faraday's law-
and 
So, as the height increases the velocity with which it will cross the ring will also increase. 
Given
Now, from 
From equation a and b we see that velocity when dropped from is 10 times greater when height is 40 
so, emf will also be 10 times less as compared to when it has fallen
Answer:
Longitudinal waves have the same direction of vibration as their direction of travel. This means that the movement of the medium is in the same direction as the motion of the wave.
Answer:
State A = piece of metal; State B = air
Explanation:
For the three main states of matter here's how it breaks down.
Solid - Cannot be compressed and retains its shape
Liquid - Cannot be compressed and does not retain its shape
Gas - Compressible and does not retain its shape.
Knowing this State A has to be solid. Only one of the options has A as a solid, so that's the answer. Worth knowing state B is a gas though, only one compressible, just like solid is the only one that retains its shape.
