Gravity is confusing.?

Question

How does gravity work the same for a human to an ant, or a car to a pop can. you would think the gravitational pull would have to be different for bigger or smaller objects.

Not falling, but why doesn't the ant smash under the same presure as the car?

Answer 1

Gravity is confusing. I know that most of the answers that you are receiving are correct in part I have not read any that might completely be answering your question. If you are confused about crushing pressure between an ant and a man then several of the explanations probably went over your head; I know that some of it sounded like “jibba jabba” to me.

I haven’t taught physics for 30 years nor am I a physicist, heck, most days I can’t even remember my own phone number but I might be able to explain to you and give you something that you understand.

First, there are several different theories on gravity and there is indeed a difference in the way gravity and gravitation act upon large and small masses. There is also a difference in the way “gravity” affects objects on earth and the way objects are affected in space. People will yell and scream that this in not true but others much smarter than I have written huge volumes of journals on this subject.

I will discuss objects on earth only since, frankly, interstellar gravitation is beyond my pitiful intellect. Simply put the human and the ant are “falling” toward earth at the same rate. How can they be falling if they are both on the ground? Well in truth no movement is taking place but that is because the earth is falling toward them also and a state of equilibrium is reached at the surface.

We also know through theory and experimentation that objects, regardless of their “mass” will accelerate at equal rates if dropped; this of course is dependant upon the lack of outside interference (air molecules, dust, tree limbs, etc). Also, of course the farther away from the earth’s surface (point of equilibrium) the objects are the rate of acceleration will change. This is because the earth, the human and the ant’s masses will affect each other less as the distance increases. Make sense?

So, the surface of the earth is dense enough to overcome any affect (gravitational attraction) between it and the human or the ant. This is another reason why an object of very high mass will sink into soil deeper than an object of lower mass, high mass requires a greater force of equilibrium to be reached (you can catch a fly ball but don't try to catch a cannon ball!). This is also why you can’t walk on water (not dense enough to overcome the “acceleration” or falling of yourself toward the center of the earth) but yet an ant can, it is much less dense than you (has less mass therefore requires less force to reach equilibrium with the earth). By the way, gravitational mass does not change but weight does because of the force of acceleration (falling) upon an object.

Pressure is equal to Force / Area. Force is the influence that causes a body to accelerate. So we know that an ant has less mass than a car and therefore requires much less force to accelerate than a car. Think of driving a wooden post into the ground. If the post is blunt it will take more pressure to overcome the density of the soil than if the post has a sharpened tip because the area will be greater. So the pressure to crush the ant would be different than the pressure required to crush a car. I’m guessing that it takes more pressure (not force) to crush the ant because the area that is affected is very, very small compared to that of a car. Pressure is given in terms of Force / area such as lbs/in^2.

This is a very crude explanation but I thought that you might be looking for some visuals rather than a bunch of formulas.

Answer 2

Other than the fact his answer is very wordy, I have no clue why anyone would give Dr. Spock a thumbs down. Clearly that voter has no clue what a good answer should look like in this case. Dr. Spock is right on point.

Gravity does not act differently on bigger and smaller objects. It does act differently on bigger and smaller masses however. In fact that difference, you know as differences in weight. Weight is nothing more or less than the force due to gravity. It's equation is W = mg; where m = mass, g = a gravitational acceleration (9.81 m/sec^2 on Earth's surface), and W = what we call weight.

So you can see, if M>m, where M = the mass of the car and m = the mass of the ant, the relative forces of gravity will be Mg>mg, or W>w; where W is the weight of the car and w is the weight of the ant.

By the way, discounting drag forces, we can see that both the ant and the car will fall to Earth at the same rate of acceleration. Why? Because W/M = g, the acceleration of the car falling and w/m = g, the acceleration of the ant falling. Thus we have W/M = w/m = g; they both fall with the same acceleration. But this is true only if the two bodies fall in a vacuum, where there is no drag force.

Answer 3

Its gravity does no longer advance. It has, if some thing, a lot less mass and subsequently a lot less gravity. An merchandise orbiting a 50 photo voltaic mass megastar at 2 hundred million miles would sense a similar gravitational allure as an merchandise orbiting a 50 photo voltaic mass black hollow on a similar distance. Distance is the most important. Gravity acts in route of the centre of mass. The closer you get to the centre the superior the gravitational allure. Halve the area and also you quadruple the rigidity you sense using gravity. For products made up of familiar remember, which incorporates planets and stars, you run into the exterior at the same time as nonetheless a significant distance from the centre. With a black hollow you could get lots in route of the centre. The closer you get the more desirable the gravitational allure you sense, till ultimately it really is so reliable even gentle won't be able to damage out. Take the solar as an social gathering (it has inadequate mass to grow to be a black hollow, although this is going to do for this). It has a radius of about seven-hundred,000km. If all its mass were condensed right into a black hollow it may have a radius of below 3km, or about a million/230000th its modern-day radius. do not ignore that in case you halve the radius you quadruple the gravitational allure on the exterior, so that you'll imagine only how a lot more desirable allure you'll sense once you get that close. So, the secret isn't that it has more desirable gravity, yet that it really is so condensed you could get a lot in route of it.

Answer 4

Good answers here. In a nutshell: The weight of an object is the force between it and the Earth. Since an ant does weigh differnt from a car, Gravity does treat them differently. They would fall (with no air resistance - like in outer space) at the same speed because of the fact that you have to pull stronger on something bigger to get it to move. Since its the same force pulling as is giving them weight (saying the same thing two ways) the bigger pull on the car pulls it at the same speed as the smaller pull on the ant. There are special effects of general relativity (pun) which say almost but not quite the same thing. I'm guessing that if this wasn't true - sombody help me here - that either small things would float off into outer space or big things like the moon and the Earth would crash together. (or vice versa) but thats speculation because that doesn't happen in this universe, Scotty.

Answer 5

I stood on a weighing scale. It read 60 kg.

Then I placed an ant gently on the weighing scale. It didn’t’ read.

I understood that the scale is not sensitive enough to read the weight of the ant.

However, I and you know, different objects weigh differently.

A car weighs many times than the weight of a pop can.

The gravity pulls a man with a force greater than it pulls an ant.

Hence it works differently with different objects.

Gravity does “NOT WORK” the same for man and an ant.

If two objects having different weights are dropped from certain height, the gravity pulls the heavier object with a heavy force and lighter object with less force.

(Incidentally, that is the reason one is heavier and another is lighter)

The interesting thing is (in the absence of air resistance) both reach the ground at the same time irrespective of their heaviness.

For falling bodies, the rate of change of speed is the same for all objects and not their weights.

Answer 6

A heavier object WILL NOT fall faster than a light object. That is a myth. Heavy objects fall at exactly the same rate as light objects, the only difference being due to air resistance. A feather has much more air resistance than a brick, so it falls slower.

The gravitational pull is proportional to the mass of the object. What we call weight is actually the force of gravity. Bigger objects are pulled with a stronger force than smaller objects, however, bigger objects have more inertia than smaller objects. So if you do the actual math, the mass of the object cancels out and you are left with a constant acceleration no matter what size or weight an object may be. On earth, objects accelerate at about 32 ft/sec² or 9.8 m/sec².

Answer 7

The gravitational force between two objects depends upon to things, the amount of mass an object has (the amount of matter in an object) and the distance between the two objects. There is in fact a different amount of gravitational force on an ant than there is on a human. Weight is the measure of the force of gravity on an object when something weighs more than something else there is a different amount of gravitational force on them. However a heavier object will not fall faster than a lighter object even though common sense tells us that the heavier object will fall faster.

Answer 8

The weight (W) of an object = mg where m is the objects mass and g is the gravitational force

Therefore, W = mg or W is directly proportional to the mass of an object since gravitational force is constant and stays the same

Thus, if an object's mass is heavier than another object then its weight would be heavier than the lighter object

Heavier objects therefore have to counteract the greater force or they would fall to the ground. If a poor ant was able to exert the force we have to exert to counteract our weight then that ant would likely jump high off the ground.

On the other hand if we only exerted the force needed to support an ant's weight, we would fall to the ground.

Answer 9

No because the force of gravity is equal no matter how big or small an object is. for example, a penny is dropped from a 747 passenger jet at the same time as a person jumps from the same jet. since the force of gravity affects the penny and the person equally, they would both land at the same time.

Answer 10

As a teacher who has taught a much-loved and much attended course on "Gravity" for almost thirty years, I feel like holding my head in my hands and weeping, when I see the misunderstandings that there are about it.

1. *** FORCE OF ATTRACTION ***

What Isaac Newton showed (and I simply don't have the time and space here to explain the powerful arguments by which he arrived at this FUNDAMENTAL HYPOTHESIS), the GRAVITATIONAL FORCE (GF) between two objects, of mass M and m respectively, say, is:

GF = GMm / R^2, ........(GF)

where G is the "Gravitational Constant," and R is the distance between them.

(Experts will want to put in lots of hemming and hawing, but this is the essence of it, for present purposes.)

This is a MUTUAL, if EQUAL and OPPOSITE force, meaning that each object experiences the same STRENGTH of attraction, although naturally in OPPOSITE directions: they are EACH attracted to the OTHER.

Notice that the mutual force has the PRODUCT of both masses concerned, in it. In effect, THAT'S what makes it MUTUAL.

O.K.; we're done with the MUTUAL force; now to its VERY DIFFERENT EFFECTS:

2. *** ACCELERATION PRODUCED BY A FORCE ***

Newton's 2nd law of Motion (simplified version) about a force F operating on a mass 'mass' says that:

Force = 'mass' x acceleration, or F = mass x a, ........(N2)

where 'a' is the acceleration that will be caused by that force.

(I'm writing 'mass', because I used the symbols M and m already, above. I don't want you to think I'm only writing about one of them! So I've used the neutral word 'mass.')

There are two cases to consider, with this "mutual force" applied to one of the constituent particles producing it.

Before proceeding, let's agree that 'M' can be M_e, the mass of the Earth, and R = R_e, the Earth's radius (the distance objects at the Earth's surface are from its centre). The symbol 'm' can represent the mass of the fly OR the man; we can leave it to be either of these to start with, and just look at those conclusions.

The key thing is, that BOTH of them (man and fly) are being attracted by the SAME object, the Earth. We now look at the ACCELERATIONS the mutual force produces in (i) 'm' (man or fly), and (ii) the Earth:

(i) Putting the mutual force (FG) into (N2) --- operating on 'm' ---we obtain:

G M_e m / (R_e)^2 = m a(m)

where a(m) means "acceleration of 'm.' So,

a(m) = G M_e / (R+e)^2 (!) :

It DOESN'T depend upon 'm'; THAT cancelled out. THAT'S WHY (ignoring air resistance, which messes things up), ALL things in the Earth's vicinity FALL to Earth with the VERY SAME acceleration, commonly known as 'g.'

It's in that sense, and that sense only, that "gravity work(s) the same for a human to an ant, or a car to a pop can." Putting it another way:

The FORCES are very different, but the ACCELERATIONS produced are EXACTLY THE SAME.

So, you're quite right that "the gravitational pull [is] different for bigger or smaller objects" --- by which you should really mean "bigger and smaller MASSES." But because the forces are proportional to each mass ACTED UPON, those masses cancel out, leaving the gravitational accelerations in a vacuum absolutely identical.

In fact, of course, this is no coincidence. Galileo had already observed the falling of a feather and a coin in an "evacuated tube," essentially a vacuum, and noticed that unlike in air, they fell in the tube at UTTERLY INDISTINGUISHABLE RATES.

So, for Newton and Galileo, this equality of m's accelerations near Earth was a GIVEN: the Law of Gravity, whatever it was, had to be constructed so that it would yield this always observed result, that (neglecting air resistance again) all things near Earth fall at exactly the SAME RATE, independently of (a) its mass, or (b) even WHAT that mass is MADE OF.

So you see, once you properly distinguish between the FORCE and the ACCELERATION it causes, gravity is no longer confusing: the different strengths of the force for different masses nevertheless conspire (indeed, are tailored) to produce the very same accelerations for everything near the Earth, as is observed. If the force didn't contain the mass of the attracted thing in its specification, you'd NEVER get that everyday observed result (again, neglecting air resistance).

With air resistance, the feather flutters gracefully to the floor, while the lead weight lands on your toe, and crushes it. (My dear disabled daughter has inadvertently demonstrated this last effect three times at her remedial bowling classes.)

Live long and prosper.

*** POSTSCRIPT ***

Don't add a self-contradicting additional "detail" an hour after we've all been busy answering you. You said that the effects on the ant and the car were the same, now you're saying they're different. Make up your mind! In fact, I suspect that you've completely switched the context on us all. The effects are "the same" if you ignore air resistance. But if you DON't, and the ant and a two ton car fall to Earth from say, 100 feet, the car will smash into the ground at about 55 mph. The effects will be just the same as if it had run into a brick wall at 55 mph, or had a collision with a 50 ton truck at 55 or so mph. Meanwhile, air resistance will save the ant; its "terminal velocity" will be quite small (not terminal --- for it! --- in fact), and it will land quite safely on the ground.

The British biologist J. B. S. Haldane wrote a fascinating popular article many years ago about the very different effects of (a) gravity, allowing for air resistance, and (b) surface tension, on small animals or insects of different sizes. For the latter, he pointed out that we climb in and out of our swimming pools with unthinking ease. For small insects, it's quite otherwise. He wrote dramatic descriptions of them struggling, in utter futility, against this dreadfully strong sheet-like trap that had them in its grip, so that they could never escape again. Their heroic struggles all proved in vain. Think of that the next time you casually drop some small creature intruding into your bathroom, into your toilet.

And thanks, Scotty, for your contribution. I always knew you could engineer a good answer. Glad to see that you're still taking your dilithium crystals in the old folks home. Give my regards to McCoy --- is he still impossible as ever?