If you think about it, irregular galaxies dont really have a describable shape, as you can tell by the name. So B.
Answer:
Explanation:
Given
mass of children 
distance between two children 
suppose small child is at a distance of x m from pivot point
so torque of small child and heavier child must be equal
I uploaded the answer to a file hosting. Here's link:
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Firstly they have a acceleration downwards due the force downwards due they gravitational field acting on it's mass.
as it falls it gains speed, and as it gains speed the air Resistance which is a upward force actin on the drop increases, eventually the rain drop's upward and downward forces are balanced and hence there is no RESULTANT force therefore no acceleration, so the drops falls in constant speed (terminal verlocity is a better term)
Are you wondering that why is the raindrop still moving given that the forces are balanced? If so according to Newton's 1st law an object will keep moving or Remain at rest until a RESULTANT force acts on it.
