Why do Objects Fall at the Same Rate in a Vacuum?

Why do Objects Fall at the Same Rate in a Vacuum?

When two objects in a vacuum are subjected to falling, keeping height,  location, and the earth’s gravity the same, both will always have the same speed; however, since air resistance varies from object to object, the acceleration and speed at which the objects are falling will also be different.

Galileo once proposed that all objects under the action of gravity will fall and accelerate downwards at the same rate irrespective of whether they are heavy or light. He supposedly dropped both heavy and light objects in a very famous experiment from the Leaning Tower of Pisa and proved it.

Some Background Info

Mass is the quantity of matter that an object contains, is typically constant in an object, and does not change.

Weight is the measurement of gravity that is acting on a particular object.

Take it this way: The mass of your body doesn’t change whether you are on earth or the Moon, while your weight on earth measures heavier because the gravity on earth is much stronger than the moon.

Why is this Statement True?

An object with more mass feels a more potent downward force from gravity. However, this amount of mass also makes it harder for the object to accelerate. (Here “accelerate,” refers to the rate of falling of the object).  So for a heavy object to fall, both the gravity pull and the toughness to accelerate the object should perfectly balance each other out, resulting in the simultaneous acceleration of the object (Newton’s second law).

But what we see every day, this explanation seems to defy the statement, correct? We all are familiar with this experiment, and its results are known to everyone. Drop a penny and feather simultaneously, and as understood, the penny will hit the deck long before the feather.

No, no, Galileo and Newton were right; it’s just that their model is simple; their statement doesn’t take the whole picture into account. Newton’s second law only holds if the two objects are under the influence of gravity alone and no other force is acting on the objects. The objects are falling through the air; air resistance will play its part in the acceleration since objects like feathers are more affected by air resistance. To understand the actual picture of Newton’s second law, let’s try the same objects, but this time air is not involved! Instead, we’ll, we’ll mean we’ll use a vacuum chamber.

Why a Vacuum Chamber?

A vacuum chamber can ideally provide the conditions required for demonstrating the Newton law as it will suck out some air, creating less air resistance. The less the air, the less the resistance will be, and the closer the object’s falling rate will be! So if you managed to get an ideal place where gravity will be the sole factor and no air at all, you could call the object in a free-fall situation, and you would prove Newton’s 2nd law true. Let’s understand this through an experiment and equation. Consider two boxes of different weights.

  • Box1 of mass 2 kg: Pull of Earth is 20 newton
  • Box2 of mass 4 kg: Pull of Earth is 40 newton

Please note that the box with more mass has double the gravitational force pulling on it. So, I know it is very tempting to predict that the heavier one will fall more quickly. But, you forget that the larger one has twice as much mass as the lighter one to set itself into motion to accelerate at the same rate as the lighter one.

Thus, a force of 20 newtons on a 2 kg mass has the same effect as a force of 40 newtons on a 4 kg mass. Using Newton’s second law of motion, we can calculate the acceleration in each of these cases. Look at this relationship for a better understanding

acceleration = force/mass

  • For the Smaller Mass,

20 N/2 kg= 10 m s-2

  • For the Larger Mass,

40 N/4 kg= 10 m s-2

Both objects fall with an acceleration of about 10 meters second-2 because acceleration is a result of gravity. And if the air resistance force acting on the falling object is negligible, you can obtain the value.

Do Objects fall at the Same Rate?

All objects fall free at the same rate, irrespective of the difference in their masses. So the value 9.8 N/kg for the gravitational force at Earth’s surface causes a 9.8 m/s/s acceleration of any object placed there; this is often called the ratio of the acceleration of gravity.

What Falls Faster in a Vacuum?

A feather and brick are dropped together in an area where air resistance exists; the feather will fall more slowly because of the air resistance. However, if. However, if the same objects were dropped together in a vacuum since the air has been removed, they would fall at the same rate and hit the ground simultaneously.

Do heavier objects fall faster in a vacuum?

That’s not always the case. Sometimes heavier objects do not fall to the ground as quickly as you think! When no significant air resistance is present, objects dropped from the same height will simultaneously fall to the earth.

What forces are involved in a falling object in a vacuum?

A falling object in a vacuum is subjected to only one external force, the gravitational force or the object’s weight. Thus, an object is said to be free-falling if it is moving because of the action of gravity only. Newton’s second law of motion can describe the motion of such an object.

Bottom Line

Newton observed the infamous apple falling from a tree and drew essential conclusions about the behavior of everyday objects under the force of gravity. He deduced his famous laws from this experiment, one of which we discussed above. So we can deduce that an object falling in a vacuum will have the same rate irrespective of their mass differences given the condition that no air resistance exists during fall. The air is clear now; I hope this article will solve the problem once and for all.

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