Question

Why must weight be constant if acceleration is inversely proportional to mass? What’s the effect of the weight?

Answer 1

acceleration equals to the force applied divided by mass

an object moving at a velocity of x carries the force of its mass times its speed.

when you apply a force onto an object, the increase in speed of it would be affected by its mass. Think of it this way: you apply some force onto an iron ball, and apply the same force on a plastic ball (they are of equal volume). Which one moves faster, and which one moves slower? The answer is obvious: the iron ball will accelerate slower and travel slower, while the plastic ball is faster.

The iron ball has a greater mass, so the force which makes it accelerate is deduced more. The plastic ball has a smaller mass, so the force applied is divided by a smaller number.

I hope this helps you a bit.