Faster the object from a certain height?


by Lanzzdub
Tags: faster, height, object
Lanzzdub
Lanzzdub is offline
#1
Mar25-12, 03:58 AM
P: 2
I'm just wondering for instance, if a ball was dropped from a height of 100m, would it have a larger velocity/ go faster than a ball that was dropped from a height of 1m?
Also acceleration would stay the same because of gravity. Yes or No?

Thanks :) !
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Johnahh
Johnahh is offline
#2
Mar25-12, 06:40 AM
P: 84
the ball from 100m would be accelerating at 9.81m/s/s so it will carry on accelerating at this speed until terminal velocity(when drag equals accelerating force) and then hit the ground.
The ball dropped from 1m would accelerate at 9.81m/s/s for only 1 meter.
therefore the ball dropped from 100m will be travelling a lot faster. Think of jumping from a garage roof and then skydiving the sky diver will reach a much higher velocity than if he jumped from a garage roof.
I would do the math for you but I am in a rush.
hope that clears things up.
kurtlesker
kurtlesker is offline
#3
Mar25-12, 06:50 AM
P: 32
depends on whether or not that ball reaches terminal velocity by 1m.

for example, if you dropped a feather from 1 m and from 100m, you probably won't sense a difference in final speed right before hitting the ground.

azizlwl
azizlwl is offline
#4
Mar25-12, 08:37 AM
P: 961

Faster the object from a certain height?


2 formulas normally used to solve a body in a constant acceleration.
[itex]S=S_o+ut+\frac {1}{2}at^2[/itex]
[itex]v^2=u^2+2as[/itex]

From 2nd. formula,
Velocity is proportional to the root of distant it traveled.
For 1 sec the velocity changes by 9.8m/s
1st. sec 9.8m/s
2nd. sec. 19.6m/s
Scintillation
Scintillation is offline
#5
Mar25-12, 10:11 AM
P: 26
Yes. Acceleration always stays the same at 9.81m/s.

However, Johnahh brought up an interesting point. Since the drag force is proportional to velocity, there is a certain velocity at which the drag force is equivalent to the force of gravity (mg).

At first, the drag force is not strong enough because the speed is low, but since the force increases as the speed increases, at some speed the net force will be zero.

From Newton's Second Law (Fnet=ma), if a mass has no net force, there will be no acceleration. Thus, the mass will be moving at constant speed.


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