Why do objects of different sizes fall at the same speed, even though gravity has a larger pull on larger objects?
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“larger” objects are also heavier which cancels this out.
the acceleration towards the ground is the same independent of the mass/type of the object. that is if you ignore air resistance.
The acceleration felt by any object in free fall due to Earth’s gravity is 9.8 meters/second squared, at sea level. This is determined mainly by the Earth’s mass and the distance from the center of its gravity.
The size of the other object doesn’t change that- the only difference is that say, a bowling ball, will pull the Earth towards it infinitesimally more strongly than a marble would. But in practice they both fall at the same rate, before accounting for air resistance.
Because objects require more force to accelerate them the same rate as lighter objects.
So let’s say you have one object with mass M, which has a gravitational pull G, and therefore accelerates at a rate A.
If you have a second object with mass 2M, it will have a gravitational pull of 2G, but in order to accelerate an object with mass 2M at a rate of A, you will need to have a force of 2G, which you do.
Another way to think of it is this. Take two objects of the same size in each hand. They should fall at the same rate, right? Well, why would their rate of fall change if you brought those objects in contact with each other? When you realize they shouldn’t, then you understand why a single object of double mass wouldn’t fall at a different rate either.
The force felt by gravity goes up, like you say. But an object’s *inertia*, or its resistance to being moved, goes up with its mass too, exactly as much. These cancel out and every object will fall at the same speed.
The equations are:
Force = G * mass1 * mass2 / distance²
Acceleration1 = Force / mass1
If you combine them:
Acceleration1 = G * ~~mass1~~ * mass2 / distance² * ~~mass1~~
So if you want to know the acceleration felt by one of the masses, its mass cancels out and all that matters is the mass of the other object and the distance.
Acceleration and speed is one thing, weight is another. As mentioned above acceleration of ANY object towards Earth is 9.8 meters/second squared. Same for everyone. But the weight is just your mass times 9.8. So more mass means more weight but same acceleration. (I also need to mention this is in ideal conditions, which means without air resistance etc.)
Actually, gravity *doesn’t* have a larger pull on larger objects. On Earth, in general, all objects are experiencing the same gravity (that is 9.81 m/s²). This means that when 2 different sized objects are released from the same height, both of their speeds increase at the exact same rate since gravity pulls on both objects equally as strong.
However, the impact they have when they hit the ground depends on its mass. The heavier object (which larger objects tend to be) will definitely be more destructive (think dropping a plastic ball vs a bowling ball from a height of 10 feet. The bowling ball might crack the floor while the plastic ball wouldn’t). This might give the illusion that gravity “has a larger pull on larger objects”.
Hope this helps!
P.S this isn’t a technical question but a logic question so idky people have to touch on air resistance or drag or differing gravitational pulls or whatever little nuance that affects calculations but not the delivery of a physics concept to the general public. It’s an ELI5 thread ffs, not an online Physics Forum.
F = m×a
F_grav = gamma×M×m/r²
a=F/m
a=F_grav/m
a=gamma×M/r²
The acceleration of a single object in a gravitational field does not depend on its mass.
Making sense of it, more massive objects require a larger force to accelerate them, but gravity acts with a larger force on more massive objects.
But why is it so exact? The real thing is that gravity isnt a force but space-time curvature. And things in a gravitational filed do what they would do anyway move in a straight line. The straight line happens to be curved relative to a flat geometry but it is straight on the curved surface.
The Newtonian answer is that the increased gravitational pull has to act on a larger mass, so the acceleration ends up the same. a = f/m, but fn/mn = a also.
The Einsteinian answer is that the masses are irrelevant (as long as they’re insignificant compared to the planet or moon) because they’re simply moving at constant speeds through curved spacetime, and it’s actually the planet/moon’s surface that accelerating up towards them.
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