|
By:
I must say, "it makes no difference" certainly is the degree anwser. Horizontal forces and vertical forces are independent of each other. It's hard to see past this really as it's pretty fundamental to physics. If any one can show otherwise you will get a nobel prize for it!
|
|
By:
night guys sleep well I hope it does not effect my dreams
|
|
By:
I hope it does, and you have exciting dreams about golf balls! Well, it could be worse., it could be Kerry Catona.
|
|
By:
Ball travelling horizontally will have lower air presure on top and bottom (assuming no spin) due to the speed compared to vertically droped ball. Therefore gravity will pull it downwards with less resistance =hits ground first.
|
|
By:
why would it have less pressure top and bottom?
|
|
By:
o level? more like A level
|
|
By:
The speed will not change the air pressure I don't think. Why do you think it will?
|
|
By:
Air flow round ball, has to go further like aeroplane wing section.
|
|
By:
Would the denser air below the ball apply more friction (drag) to the underside?
|
|
By:
but if pressure top and bottom decreases or increases, net difference is nothing.
r u thinking of aerofoils? that is the profile of wings and that, bernoulli theorum, and that creates a pressure difference, but only if the profile is right. a ball isn't like that, well not a normal ball. |
|
By:
With wings the difference in pressure is created by the air travelling different distances over the top and bottom of the wing, due to its asymmetryc shape. This is not the case with a golf ball.
|
|
By:
The air above the ball is less dense than the air below it due to height difference.
|
|
By:
naydam is taking the p.iss
|
|
By:
Yes, but it is for the vertically dropped ball to.
|
|
By:
So the denser air will cvreate more friction.
|
|
By:
Naydam is not taking the P. He may be wrong...but genuinely so.
|
|
By:
air flowing past the horizontal ball still reduces the pressure immedately next to the surface top and bottom,
Blow across the top of a piece of paper on a table and it lifts. It is not further across the top than the bottom, but the air is static on the bottom. speed reduces the pressure. |
|
By:
Yes, but it will for the vertically dropped ball in equal measure.
|
|
By:
Horizontal air flow will the the same for a golf ball unless it is not perfectly round.
|
|
By:
In the case odf thje dropped ball, there is no flow over the top of the ball.
|
|
By:
Yes. But the density of the air above the ball is greater than that below it because they are at different altitudes. Air get thinner as height increases.
|
|
By:
No, but the horizontal flow cancels out in the alternative case as the ball id symmetric. Now, in the case of the lecturer batting a ballown sideways while dropping one we would not expect them to fall at the same rate, as the balloon is not symmetric. But with a golf ball we would.
|
|
By:
If the ball is travelling through air there will be more drag on the bootom half than the the top because the air is thicker (denser). This creates more friction (drag) and should cause the ball to rotate. I can't figure out if this rotation would give 'lift' but I suspect that it would. This is probably related with why golfballs have dimples. I'm pretty sure it is to utilise this phenomenum to give longer flight of thje ball.
As I said ...I don't know. Just gut feeling. |
|
By:
Just seen the time. Gotta go! Goodnight all. :-)
|
|
By:
Actually, i think you are right. Dimples do create lift, so a ball hit horizontally would take longer to hit the ground.
|
|
By:
Wouldn't the gravitational pull on the horizontal ball be less(at least for a short period) due to the initial energy provided by the explosive propulsion.
|
|
By:
No
|
|
By:
**
|
|
By:
I am assuming the golf ball weighs 0.1 of a kilo and that acceleration due to gravity is 10m/s/s to make the sums easier.
In the same spirit I assume that the terminal velocity of the golf ball is 100 m/s. Therefore at a speed of 100m/s the force down due to gravity and the force up due to air resistance are both 1 newton O.1 kg times 10 m/s /s= 1 kg m /s/s. Air resistance is proportion to the square of the golfball speed. Suppose they were both falling downward at 30 m/s however one of them had a horizontal velocity of 40 m/s. The speed of the first golf ball is just 30 m/s the second ones speed will be 50 m/s . (Pythagarus) The force of air resistnace on the dropping golf ball will be .3*.3 = .09 of a newton directly upwards. It will be accelerating down at 9.1m/s/s The force of air resitance on the second golf ball will be .5*.5= 0.25 of a newton With a vertical component of .15 newton and a horizoantal component of .20 newtons It will be accelerating down at 8.5 m/s/s At any given point of the jorney down air resistance will mean the dropped gold ball will be accelerating downwards faster If the eiffle tower was the one on mars where Elvis lives it should of been clearly stated in the question |
|
By:
V.good work Honest Novice.
So it was to do with air resistance being proportional to speed, and there fore a scalar quantity (50m/s/s rather than 30 m/s/s) and therefore not simply a matter of saying the horizontal and vertical components are the same for both ball. You just put it better than me, cheers Honest. |
|
By:
I think if this thread proves one thing, it's that RD can get drunk and yet keep arguing for an impressively longer time than I
|
|
By:
:)
|
|
By:
Ty Roby I notice you always support an underdog woof woof
|
|
By:
Back again. Okay, so the golf ball should see more drag on it's underside than it sees on the top. Air has density. The density of the air reduces as it gets higher. The part of the ball at the bottom will always 'see' more friction, due to flying through thicker air. The dimples don't cause this, but they do enhance the effect.
If the above is true, the question now is: Does this spinning action, whilst passing through the air, create an aerofoil effect? I think it will. This will create 'lift' (or 'loft') and extend the flight time of the ball. Therefore it hits the round after the dropped ball. Sadly, if all this theory is correct, I have proved my original thoughts totally wrong. :-( |
|
By:
naydam, impressive, but if you're lazy like me and just look it up, there's a whole bunch of stuff acting on the projectile
http://en.wikipedia.org/wiki/External_ballistics |
|
By:
Oops. missed a bit. *This causes the ball to spin.* (inseret before dimples bit)
|
|
By:
NOW he tells me! I was tossing and turning and falling and flying all over the place when I went to bed. :-)
|
|
By:
By now ,both golf balls would be insane :)
|
|
By:
I can't believe there are nearly 300 posts on this thread ! :0
|
|
By:
Sparky. Just had a look at that link. Very interesting but it doesn't seem to cover spherical objects. Think I'll try something like 'Golf ball flight' when I have time. Might be something there.
|