The only statement that makes sense as to which one describes an effect of changes in Earth's magnetic field is the first one - <span>Southern lights are seen at high altitude places like Alaska.
Normally, Southern lights are seen around the South Pole, which means that it is quite odd for them to be seen in Alaska, which is near the North Pole.</span>
I only know #2 and #4.
2.) cells
3.) cells, life , existing
Sorry that i dont know the rest but i took a test on this not to long ago, and i tend to forget stuff once i take a test on it.
Answer:
Explanation:
a ) work done by gravitational force
= mg sinθ ( d + .21)
Potential energy stored in compressed spring
= 1/2 k x²
= .5 x 431 x ( .21 )²
= 9.5
According to conservation of energy
mg sinθ ( d + .21) = 9.5
3.2 x 9.8 x sin 30( d + .21 ) = 9.5
d = 40 cm
b )
As long as mg sin30 is greater than kx ( restoring force ) , there will be acceleration in the block.
mg sin30 = kx
3.2 x 9.8 x .5 = 431 x
x = 3.63 cm
When there is compression of 3.63 cm in the spring , block will have maximum velocity. there after its speed will start decreasing.
