# Mass and free fall question

by tengtou
Tags: fall, free, mass
 P: 4 A ball of mass .5 kg is dropped from a height of 5 m. What is the greatest velocity it will have just before hitting the ground? vf squared = vi squared + 2ad vf squared = 0 squared + 2(9.8)(5) vf = 9.8 m/s So the greatest velocity is 9.8 m/s, right? I am still very confuzzled and I think this is the right answer because where did the mass go? Or it doesn't even matter? Can someone verify? Thanks!
 HW Helper P: 4,430 Yes. Mass does not matter in the free fall under gravity. All the body get accelerated equally.
 Sci Advisor HW Helper Thanks P: 24,514 Welcome to the forums! No, mass doesn't matter. The acceleration downwards is g, independent of mass, ask Galileo. It's a purely kinematical problem.
P: 4

## Mass and free fall question

Thanks! So is my answer correct?
 Sci Advisor HW Helper Thanks P: 24,514 Approximately, yes. I would round the answer to 9.9m/sec. But that's a detail.
 P: 4 Sweet! Thanks!
 P: 4 I don't know why the question had mass in it. Trick question or something haha.
 Sci Advisor HW Helper Thanks P: 24,514 In real world problems YOU have to figure out what's important and what isn't. It's just practice.

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