If you drop a bowling ball and a tennis ball from the same height, which hits the ground first? The idea of the question is you’d assume the heavier object would fall faster, but as I was taught as a kid, they both hit at the same time. But now I’m thinking that doesn’t make any sense.
If I remember correctly, the two main variables affecting gravity are mass and distance. Since we’re holding distance constant with the bowling ball and the tennis ball, that means I’m supposed to believe that two objects with different masses have the same acceleration? Well, what would hit first: A bowling ball dropped from one meter on Earth or a bowling ball dropped from one meter on Mars? The bowling ball on earth obviously, as the increased mass of Earth versus Mars results in increased acceleration. Because mass matters.
It seems to me the fallacy of saying the bowling ball and the tennis ball fall at the same speed is thinking the mass of the Earth is so great compared to the two balls that you can discount their mass. But, scientifically, that can’t be true. The bowling ball being more massive is going to pull back on the earth more than the tennis ball and thus accelerate faster (or would the tug slow it down in any way?). It won’t be discernible to the human eye, but the bowling ball’s fall at least won’t be gravitationally the same as the tennis ball’s.
So, to whomever taught me objects all fall towards earth at the same rate regardless of mass, I am now formally calling shenanigans. That’s either wrong or requires much more of an explanation.
I’m a creationist and this is science. You’re just speaking jibberish to me.
Yeah, but lifting the bowling ball 1m requires an acceleration to get it off the ground. An acceleration requires a force. For every force, there is an equal and opposite force – in this case, it is your feet pressing against the ground. Your feet pressing against the ground causes the Earth to move by the same amount that the gravity of the bowling ball is going to attract the Earth.
Unless you’re as gimptastic as Obama and can’t lift a bowling ball 1m off the ground. Then the whole argument pretty much goes down the toilet.
It’s a conspiracy man. The government just *wants* us to believe that everything falls at the same rate. They’re trying to socialize gravity.
It’s down to acceleration. Gravity applies a force (M*M/(r^2)) so, yes, there is more force applied to the bowling ball than the feather. That’s why a bowling ball weighs more. However, acceleration is force divided by mass (F/m=a). Since you are dividing by the mass in each case (bowling ball and feather) the large force dividing by large mass in the case of the bowling ball and small force divided by small mass in the case of the feather you wind up with the same acceleration in each case. This has been your physics lesson for the day. 🙂
The force exerted on the mass of any two point objects is proportional to the masses of the two objects, and inversely proportional to the square of the distance between them.
So, let’s say one of the objects is the Earth, and the other is a bowling ball. We’ll call the mass of the earth
M, and the mass of the bowling ballm. We’ll call the distance between the two objectsr, and the constant of proportionalityG. Thus, the force due to gravity exerted on the bowling ball by the Earth will be equal toG * M----- * mr * rThe force that acts upon an object is defined to be the product of the mass of the object and the acceleration caused by that force. So, keeping
mas the name of the mass of the bowling ball, and introducingaas the observed acceleration of the bowling ball due to the force of gravity, we see that the force due to gravity exerted on the bowling ball by the Earth is also equal tom * aOf course, since the force due to gravity is equal to both of these things, they must be equal to eachother. This means
G * M----- * m = m * ar * rNow, for this equation to be true, either
m = 0orG * M----- = ar * rYou’ll note that the acceleration of the bowling ball due to the force of gravity between it and the Earth can thus be calculated without knowledge of its mass.
To recap: Although, as you say, “the two main variables affecting gravity are mass and distance,” these two main variables affect the force of gravity, not the acceleration due to gravity. Since one of the two main variables affecting acceleration due to a force is mass, any effect the mass has on the force is canceled out by the effect the mass has on the acceleration.
To rerecap: Larger masses make larger forces, but larger masses need larger forces to accelerate by the same amount.
[So are we talking the mass of the entire system? Thus, if I drop a tennis ball, measure the time, then shoot the tennis ball out of orbit, get a bowling ball from Mars, drop the bowling ball on Earth and measure the time, would the acceleration be different (assuming no other mass changes to earth)? And don’t the bowling ball and tennis ball also pull the earth based on their masses, so if dropped in different locations at the same time, the earth will be pulled more towards the bowling ball thus making it impact sooner?
There are just so many variable I just don’t get the hand wave that acceleration is the same regardless of mass when looking at the moon or Mars, mass obviously is important to the acceleration due to the force of gravity. -Ed.]
Gravity just another law to be broken….
Actually, Frank, your caveat is only true if the objects fall at different times. While you are correct that the bowling ball accelerates the earth more than the feather, when dropped *with* the feather this increased acceleration on the earth *also* decreases the time of the impact for the feather, and they still impact at the same time.*
*If we get really really nitpicky they also need to be dropped from the same space, which means we also need to put the feather inside the (hollowed out) bowling ball so that the center of masses coincide, otherwise the bowling ball will pull the earth in a slightly different direction than the feather.
Even as a kid I figured that something with more mass (not necessarily bigger) will be more affected by earths’ gravity. But yeah, the earth is so friggin huge dude!
But all this has absolutely nothing to do with the first release of large Superballs in the 60s which was awesome. They were harder than the typical Superballs they began making I think a year later. Then they got smaller. And even softer. The original Superball I could bounce off a sidewalk and lose it on a 7th story roof. That was the thing with old Superballs. You could only use them once. I think they’re all in orbit now.
Never cared much for gravity. I’m more of an inertia guy.
I always did better in history class.
Hey, what about the coefficient of friction? Is the atmospheric coefficient the same for a bowling ball and a tennis ball? It’s been thirty two years since I had Newtonian physics, and quite frankly it’s easier to ask one of y’all propeller heads than to look it up.
Oops,just re-read the post. Apparently I also forgot what “vacuum” means in those years.
Is that why I’m more attracted to big women?
I’m sure if you ask obama’s folks to do the math they can come up with the answers you want.
ps:terminal velocity is 120 mph. As an object falls it accellerates at an increase of 60 ft/sec/sec until it reaches terminal velocity.
Consider that, not only is the speed of light 300,000 km/sec, but the speed of gravity is 300,000 km/sec. (Naturally, we’re talking relativity, not Newtonian, which — incorrectly — assumes gravity propogates instantaneously.)
Given that, if the bowling ball hits first, the mass of the earth has increased by the mass of the bowling ball, changing the values affecting the force exerted on the feather. Given the speed of gravity is an absolute limit (equal to the speed of light), the changes in mass are balanced by a warping of time.
Remember that if two items are travelling at each other with each item travelling 200,000 km/sec, the combined speed is not 400,000 km/sec; it cannot exceed 300,000 km/sec. This descrepancy is accounted for by the warping of time.
By the same token, the change in the mass of the earth-feather system is accommodated by a warping of time, causing the feather to strike the ground at the same time as the bowling ball.
Or not.
I don’t really have anything to contribute to this thread, but I thought I’d let everyone know that a pair of broken binoculars impacted the ground well before several strands of hair from a dog.
CayleyGraph:
But what if instead of solving for M we solve for m, so that the mass of the earth drops out instead of the mass of the object? Then let’s say m=m1 for the feather, and m2 for the bowling.
Then we get
G*m1
—– = a1
r^2
and
G*m2
—– = a2
r^2
Clearly a1 > a2 if m1 > m2.
Frank’s intuition is correct. The bowling ball does accelerate the earth more than the feather; and therefore, dropped at separate times, the bowling back impacts first.
You are also correct that the acceleration on the feather and the acceleration on the bowling ball are equivalent as viewed from Newton’s formula. But in reality there are two accelerations involved here, and it’s a bit different when you allow the earth to move as well.
Gravity: Unfair, Unbalanced, Unmedicated, kind of like IMAO
I see one problem with all this in that there is no way you are going to vacuum up a bowling ball.
There is no gravity. The Earth sucks.
This is in no way related to the topic, but someone should inform Frank that Terminators exist. If you doubt me, read the story http://www.thelocal.se/19120.html The only odd thing is that I couldn’t believe that the Swedish would be the first to have self-aware robots…
“Gravity is a harsh mistress.”
– The Tick –
Frank-
At the risk of losing the family friendly atmosphere, the answer lies in the old joke about the mathematician, the engineer and a Hooker.
A mathematician and an engineer are placed across a basketball court from a hooker and are told they can do whatever they want with the hooker, but each time they approach her they can only go 1/2 of the distance that remains between them. The mathematician immediately despairs and cries out “it will never work, going 1/2 the distance each time I can never reach her.” The Engineer puts on a condom and says “I will get close enough for practical purposes”.
You are correct that the rates of acceleration will be higher for the heavier object than the lighter, but the difference will be too small to give a Rat’s pattooie about.
Damn, The Tick was a great cartoon and a slightly not-as-great live action show.
Humor is the only test of gravity, and gravity of humor; for a subject which will not bear raillery is suspicious, and a jest which will not bear serious examination is false wit.
Aristotle
Greek critic, philosopher, physicist, & zoologist (384 BC – 322 BC)
Did you also know that a bullet, fired parallel to the ground, will hit the ground at the exact same time as one dropped at the same instant?
Don’t believe me? Well, start running and we’ll check.
Yeah, I was very disappointed in the Tick sitcom. Except for one great line that I’ve stolen and can feel confident that nobody knows I stole because maybe 4 people saw that show.
The Tick was doing his unintelligible monologue when an admiral’s aide was going to shut him up and the admiral said, “No, I like the cut of his gibberish”
Heh.
Crap, now I can’t use that line here or all of you will know I stole it.
Don’t tell anybody else though.
[That’s an awesome line and now it’s mine! -Ed.]
What falls faster if dropped from the same height, a bowling ball or Obama dropped head first?
Obama never falls. The earth comes to him.
While we’re talking about awesome “The Tick” quotes, I just so happen to have a list of favorites carefully culled from wikiquotes:
Ah, savory cheese puffs, made inedible by time and fate.
And, isn’t sanity really just a one-trick pony anyway? I mean all you get is one trick, rational thinking, but
when you’re good and crazy, oooh, oooh, oooh, the sky is the limit.
And so, may Evil beware and may Good dress warmly and eat lots of fresh vegetables.
Arthur, you have no historical perspective. Science in those days worked in broad strokes. They got right to the
point. Nowadays, it’s all just molecule, molecule, molecule. Nothing ever happens big.
Deadly Bulb. I’m about to write you a reality check. Or would you prefer the cold, hard cash of truth?
You know, when a tomato grows out of your forehead, it gets you thinking. What do we know about anything? Life is
just a big, wild, crazy tossed salad, but you don’t eat it. No sir. You live it!
Destiny is a funny thing. Once I thought I was destined to become Emperor of Greenland, sole monarch over its 52,000
inhabitants. Then I thought I was destined to build a Polynesian longship in my garage. I was wrong then, but I’ve
got it now. I’m the destined protector of this place. I’m this city’s superhero.
Don’t make us bite you in hard-to-reach places!
Egad! A gigantic well-dressed digestive enzyme! I am in a whale!
Everybody was a baby once, Arthur. Oh, sure, maybe not today, or even yesterday. But once. Babies, chum: tiny,
dimpled, fleshy mirrors of our us-ness, that we parents hurl into the future, like leathery footballs of hope. And
you’ve got to get a good spiral on that baby, or evil will make an interception.
I don’t know the meaning of the word “surrender!” I mean, I know it, I’m not dumb… just /not in this context/!
I hate broccoli, and yet, in a certain sense, I am broccoli.
Must… defy… laws of physics!
Ninjas can breathe underwater! They can dodge bullets at point blank range! They can walk up the sides of
buildings! They can install telephones!
You’re on a first-name basis with Lucidity. I have to call him Mr. Lucidity, which is no good in a pinch.
“How ya doin’?” (To a mystic statue which he may ask any one question.
“Unsettling trend.”
[After having his head crushed for the second time in the space of an episode]
WANNABES! All of you, spitpolishing your prosthetic limbs, und whitewashing your liverspots for this wretched
back-patting, smarty-party! The true mad scientist does not make public appearances! He does not wear the ‘hello my
name is” badge. He STRIKES from below like a viper! Or on high like a PENNY, dropped from the tallest building
aroundt! He has only ze one purpose: do bad things, to good people, MIT SCIENCE!!!!
I weave a lethal net of baked goods that few can escape.
“You can’t catch me, I’m filled with tinier men!” –The Living Doll (Grandpa Wore Tights)
Hmmm, Tick quotes could be useful.
Tick to Galactacus (eater of worlds)You can’t destroy the Earth, that’s where I keep all my stuff!
Change it to, Veeshir to Obma
You can’t destroy America, that’s where I keep all my stuff!
Vaccuuming sucks.
Isn’t it weird how “vacuum” has two u’s in it?
So which would drop faster if dropped from a height of say, 100 ft onto solid concrete? — Michael Moore or Rosie O’Donnell? Harry Reid or Nazi Pelosi? Obama’s approval ratings, or GaffeBiden?
Whatever the answer, I don’t believe you. I’ll need to see proof.
Um, does no one remember when one of the astronauts dropped a feather and a hammer on the moon?
[Well, no. I wasn’t alive then. But the point isn’t that they’ll appear to fall at the same speed. -Ed.]
Raytonium: I remember it well. I watched it live on TV. Apollo 15, wasn’t it? Dave Scott used a falcon feather (the LEM was named “Falcon”) and a hammer.
Okay, time to go geek on your a$$- in high schoo algebra we learned d=rt where d is distance r is rate and t is (hopefully ) time. we went to college and learned (again I’m hoping here) that velocity v is the derivative with respect to time of the distance formula it is also defined as acceleration a multiplied by time t so we get by substitution s(t)=s(0)+ v(0)t +1/2at^2. Realizing that the only acceleration acting on the falling body is gravity we substitute the term g arriving at s(t)=s(0)+ v(0)t +1/2gt^2. taking the derivative we find v(t)=v(0)+gt. Mass appears no where in these equations and they reliably perdict the action of falling bodies.
Clear as mud, right.
Gravity is that pesky law that makes me aim higher for long range shots.
Ballistics-Don’t make me go there
Ballistics should be taught in elementary school!
Discounting the curvature of the Earth, that would be true.
Ok. I think you guys are overthinking this issue. I can resolve the controversy:
NEWTON’S GRAVITY APPLE
Ingredients:
• Several dashes Angostura bitters
• 1/2 oz. curaçao or triple sec
• 1 1/2 oz. apple brandy
Mixing instructions:
Mix all ingredients with cracked ice in a shaker or blender and strain into a chilled cocktail glass.
I think you’re really onto something here, Frank! If you are holding two objects, one a tennis ball, the other the planet Jupiter, and drop them from the same distance towards the planet Earth, I’d bet Jupiter reaches Earth first.
How about if someone – let’s say a metrosexual who throws like a girl – was to toss a baseball, lofting it up into the air. Would the baseball fall faster than his approval ratings, or would they both fall at the same speed?
Is gravity the reason why my man boobs are sagging?
# 8 Corona,
Superballs are awesome, the ones in orbit are probably the reason the Andromeda Galaxy is drawing near.
All irrelevant. The wacky string theorists have chucked Newton out the window without any discernable evidence and installed their religion in its place despite any given proofs. 🙂
The earth pulls both towards it with the same acceleration. The difference between them is how much they accelerate the earth towards themselves. Which is negligible.
I’m pretty sure that Newton got this one right, with a little belated help from Einstein. That was fun!
Now do the tree in the forest!!!
The example of the bullet fired parallel to a non-curved earth would also be true within a vacuum… however in the atmosphere, the high velocity and vorticity caused by rifling creates low pressure zones behind the bullet’s parabolic shockwave. As the bullet neared the ground you would get some almost negligible suction below the bullet which is not counteracted above, which would accelerate it towards the ground more quickly than the dropped bullet.
Also, the aerodynamic effects on either bullet (depending on the type’s particular shape and center of gravity) would cause it to point down, but would be resisted by the gyroscopic effect of the fired bullet’s rotation, thus dissipating energy AND changing the coefficient of friction with the air below it.
Also to be considered, a fired bullet would be shedding mass… both from centripetal forces and from natural ablation caused by the application of heat. Perhaps only a few atoms, but shedding none the less, which would affect the coefficient of friction as it falls through the air.
As I said, almost negligible… but not identical without a vacuum.
Mass of bowling ball is negligible. Remember Significant Figures. Think of it like this: Once you are looking for accuracy to that degree you can go ahead and throw the g (earths gravity not G for the equation) constant we all know and love out the window because that is now a variable because every movement that the ball makes changes the distance adjusting the force. This is all so insignificant you could spend hours and hours plotting a function for the attractive force as the two approach, then you would have to take it back to your margin of error which would effectively give you what you would have found in the first place. Unless you have some seriously accurate measurement systems.
Your conclusion would either be due to lack of accuracy they effectivly hit at the same time or every time you drop a bowling ball a slight force hits the earth and pushes it out of the suns orbit changing the climate and causing global warming.
Huh? It’s not a hand wave. It’s math. Do you believe the law of gravity? CayleyGraph did the math to show that it leads to identical acceleration. (M is Earth mass, m is falling-item mass.) The only “hand wave” was that the Earth system wasn’t moving in the inertial frame of reference. If you don’t concede that, though, the problem is too complex to solve, but fortunately the other factors are minor (rotation of the Earth, revolution around the sun, wobble, bodies outside of the two under consideration, solar wind, changing mass of the earth, whether the feather lands vertically or horizontally, molecules leaking into your so-called “vacuum”). You could introduce more than two bodies but (a) the additional negligible factors are overwhelmed by other imperfections and (b) physicists can’t handle threesomes.
As with anything else, though, our intuition is based on what we see: Things falling in a non-vacuum nowhere near the speed of light at macro scale. So things outside of those terms often seem counterintuitive.
No one has ever seen the bowling ball hit the earth. It always lands on your foot.
Capitalist B – If you dropped Jupiter and a tennis ball towards Earth, they would impact at different times. Jupiter’s got more mass, therefore we’d fall towards Jupiter….and since you are dropping the tennis ball side by side with Jupiter towards earth, the tennis ball’s got a headstart on us…. 🙁
curvature of the earth is negligble over the distance a bullet would travel. Trying to add to much complexity just bogs down the model.
Haven’t read a lot on string theory yet. Just reading Feynman’s QED gives me a headache
Inside every bowling ball lives a liberal – screaming to get out. Hence the slower acceleration to earth as the mass is so replete with hot air. As the bowling ball approaches earth, the golf ball wizes by it because the conservatives withheld the taxes to the golf ball, and THIS is why the golf ball always lands first.
I remember the formula that objects in freefall accelerate at the rate of 32 feet per second per second.
But is that a universal constant or does it just apply to objects on Earth?
Things the astronauts on the Moon dropped seemed to fall more slowly than on Earth.
Quick-ish explanation: if there were only 2 objects in the universe, the Earth and the bowling ball (later replaced by a feather), AND it’s in a vacuum AND the non-Earth objects are dropped serially, not at the same time, then Frank would be correct: this would be a 2-body problem in which each non-Earth object would move toward Earth with the same acceleration, BUT the Earth would also be accelerated toward the non-Earth object with a very small but different (depending on the mass of the non-Earth object) amount of acceleration, which would cause the bowling ball to collide with the Earth more rapidly than the feather (by a really, really tiny amount). However, once you allow more objects into the universe (behold the power of the thought-experiment!) then things start to get much more complicated, and they get more complicated in the direction of equalizing the time for feather-fall and bowling-ball-fall. Essentially, the extra bodies (and here I’m mainly talking about the pre-nuked Sun, so don’t be thinking that this is ANOTHER reason to nuke the moon…) tend to lock the Earth into position (relative to most sensible coordinate systems for the problem), so that ITS acceleration due to interaction with the non-Earth body (which was the source of the difference) is reduced greatly. So, your physics teacher wasn’t REALLY lying to you, but just making an unstated (but quite reasonable) assumption that the acceleration of the Earth would be neglected, either because it’s so much smaller than the acceleration of the non-Earth body, or because it’s further damped by interaction with the rest of the universe.
All comments on gravity on this sight just might be missing something. Just as people that were trying to make flying machines before the Wright Brothers didn’t quite understand that speed through the air might have something to do with lift. If there is a government conspiracy it is doubtful
I don’t think their that smart individually. Eliminate all variables and use one planet (Earth) and conduct The bowling ball – tennis ball experiment in
a vacuum over much greater distances than 1 -100 meters say one half mile to a mile and if my theory is correct the larger mass will hit the ground
slightly sooner than the smaller mass. This experiment has never been shown by a non government group (ie not astronauts) to be accurate (true) over
large distances and if I’m correct. the masses will hit at seperate times and then you can start asking yourself why? I have some theories on this but that
opens up a whole other can of worms. Remember a large airplane won’t fly untill it reaches the proper speed through the air.
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