Register to reply

Mass and free fall question

by tengtou
Tags: fall, free, mass
Share this thread:
tengtou
#1
Feb7-08, 10:23 PM
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!
Phys.Org News Partner Science news on Phys.org
Hoverbike drone project for air transport takes off
Earlier Stone Age artifacts found in Northern Cape of South Africa
Study reveals new characteristics of complex oxide surfaces
rl.bhat
#2
Feb7-08, 10:55 PM
HW Helper
P: 4,439
Yes. Mass does not matter in the free fall under gravity. All the body get accelerated equally.
Dick
#3
Feb7-08, 10:57 PM
Sci Advisor
HW Helper
Thanks
P: 25,251
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.

tengtou
#4
Feb7-08, 11:00 PM
P: 4
Mass and free fall question

Thanks! So is my answer correct?
Dick
#5
Feb7-08, 11:07 PM
Sci Advisor
HW Helper
Thanks
P: 25,251
Approximately, yes. I would round the answer to 9.9m/sec. But that's a detail.
tengtou
#6
Feb7-08, 11:08 PM
P: 4
Sweet! Thanks!
tengtou
#7
Feb7-08, 11:14 PM
P: 4
I don't know why the question had mass in it. Trick question or something haha.
Dick
#8
Feb7-08, 11:29 PM
Sci Advisor
HW Helper
Thanks
P: 25,251
In real world problems YOU have to figure out what's important and what isn't. It's just practice.


Register to reply

Related Discussions
Free fall question Introductory Physics Homework 12
Free Fall Question Introductory Physics Homework 7
Yet another free fall question. Introductory Physics Homework 9
Free Fall Question Introductory Physics Homework 5
Free fall question Introductory Physics Homework 6