Answer:
6
Explanation:
Number of lines emanate from + 5 micro coulomb is 15 .
They terminates at negative charges that means at - 3 micro coulomb and - 2 micro Coulomb.
the electric field lines terminates at - 3 micro Coulomb and - 2 micro Coulomb is in the ratio of 3 : 2.
So the lines terminating at - 3 micro coulomb
= 
So the lines terminating at - 2 micro coulomb
= 
So, the number of filed lines terminates at - 2 micro Coulomb are 6.
You could use a magnetic generator or you could use hydraulic power
The energy of the system is E=5.5 J. This energy is the same at every moment of the oscillation. When the stretch x of the spring is maximum (so, when the stretch is equal to the amplitude: x=A) the velocity of the spring is zero, so all this energy is just elastic potential energy of the spring:

From which we find
The distance the object travels
Answer:
= 15 m/s
Explanation:
Considering right side(west) as positive x-axis and south as negative y-axis.
velocity of boat in still water 
velocity of stream 
now relative velocity of boat w.r.t. stream 
this velocity with which ac distance will be covered.
therefore magnitude of 
= 15 m/s