Which falls down first?
Classical Mechanics
Level
1
1kg of iron , 10kg of cotton and 20kg of wooden furniture are dropped from a height of 5 meters at the same time. You can assume that there is no air resistance and that they fall freely. Which one reaches the ground first ?
The wooden furniture reaches first.
All the three objects reach the ground at the same time
The iron object reaches first
The Cotton mass reaches first
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Without air resistance or in vaccum the only force acting on a body during a free fall is the downwards force which is equal to the weight of the body mg.
So F net = ma = mg so a = g; h =ut + 4.9 * t * t , when u = 0 , t = sqrt(h/g). So it can be seen that t is independent of the mass. However when there is air resistance the bodies will be subject to an upward drag force , which will be different for different objects and will not reach at the same time.