Free Fall Calculator

Table of contents:
The free fall calculator can be used to calculate the velocity of a falling object as well as the distance it covers while falling. This is a powerful calculator, as it automates the use of the free fall equation for the user.

Continue reading to find out more about objects in free fall and the physics behind it. Explore the amazing world of space diving (jumping from a spacecraft in outer space to the Earth’s atmosphere) and how it broke the sound barrier. We will also touch on free fall acceleration, explaining why it's taken as a constant.

If you are interested in the free fall calculator, you may also be interested in the projectile motion calculator, which is actually a free fall calculator but with the horizontal component included.

What is the free fall definition?

We describe an object in free fall as an object falling under the sole influence of gravity. Using the equation F=ma this implies that any acceleration experienced by the object is due to gravity (g) as mass is constant and the only force acting on the object is gravity.

This may surprise you, but not all objects in free fall are necessarily falling or moving downwards. You probably know that even earth is under the influence of the Sun’s gravity, no other forces are acting on the earth and there is no air resistance present. Yes, the earth is currently in free fall towards the Sun!

The next logical question is, given how long the earth has been around why hasn't it already crashed into the sun. Well, the earth’s speed isn't actually directed towards the Sun, but tangentially to its orbit.

Think of the satellites moving around the earth in an elliptic orbit or even a natural satellite like the moon, its first cosmic velocity actually generates a centrifugal force, which is equivalent to the force of gravity in the opposite direction.

Free Fall speed

When acceleration is constant (i.e. free fall of an object) it is trivial to show by using the suvat equations that the velocity of a falling object is

V = V0 + g * t


●	V0 stands for the initial velocity of the object (expressed in m/s or ft/s)
●	t stands for the time of the fall (expressed in s)
●	g stands for the acceleration due to gravity (expressed in m/s2 or ft/s2) gravity,

As mentioned earlier free fall is when a falling object is under the sole influence of gravity, hence won't be accounting for air resistance in our calculation implying that our acceleration due to gravity should be a constant value of 9.80665 m/s (approximately equal to 32.17405 ft/s). Outside of calculations in real life, falling objects often experience terminal velocity which basically serves as a limit to the velocity of an object.

Now you may be wondering what terminal velocity is. As we have outlined above the acceleration due to gravity is constant, which implies that the gravitational force acting on the object is also constant.

In reality, there is air resistance and it increases with increasing velocity as you can test by sticking your hand out the window of a car going 20km/h vs one going 100km/h. Therefore, as the falling object accelerates and increases its velocity the air resistance will generate a force equal and opposite to the force due to gravity. Applying Newton’s first law, we realize that the object stops accelerating and begins to move with constant speed. This is what is referred to as terminal velocity.

As stated before this particular calculator ignores air resistance, basically calculating the free fall of an object in a vacuum.

Free fall equation

The equation of motion with s as the subject of the formula is used when one wants to find the distance traveled by a falling object. In the event that the velocity and initial displacement of the object are both zero, it is simply 

s = 0.5 * g * t2

But. in the event that the object is already falling, this would mean it has an initial velocity that has to be included in the calculation.

s = V0 * t + 0.5 * g * t2

You should be able to see from the equations that fall distance of the object is proportional to the fall time squared. In simple terms, this means that the object falls through a significantly greater distance every second as compared to the second before.

There is an amazing implication according to the free fall formula, two different objects regardless of mass in the absence of air resistance should fall at the same velocity and thus move the same distance in a given amount of time. Astronaut David Randolph Scott performed an experiment by dropping a falcon feather and a hammer from the same height on the moon in 1971 and they hit the ground at the same time, due to a lack of air resistance on the moon.

This experiment can be tested with a vacuum here on earth.

General use of the free fall formula:

We have prepared an example to briefly explain the ins and outs when using this free fall calculator.

1.	Choosing the acceleration due to gravity. Its value is 9.80665 m/s2 on earth on average and as such it is the default value we have set in the free fall calculator. Should you feel the need to use a different value. It is editable as are all the other fields.
2.	Determining if the object has an initial velocity. V0= 0 is the default but again it can be changed as it is editable as well. 
3.	You must enter the time of the fall. For the purposes of this example, we will use 15 as the fall time.
4.	Now if we want to know the final free fall velocity, using the formula V =V0 + g * t = 0 + 9.80665 * 15 = 147.10 m/s (check with the free fall calculator).
5.	Now if we want to know the free fall distance, using the formula s = 0.5 * g * t2 = 0.5 * 9.80665 * 152= 2206.50 m (check with the free fall calculator).
6.	In the event that you have the fall distance of an object but don’t have the fall time, you can use the free fall calculator to get the time.

Highest free fall in history

While most of us settle for elevators or bungee jumping to experience free fall, Alan Eustace jumped from over 41,425 m (135 908 feet) above the Earth in 2014.

He broke the sound barrier and became the man with the highest free fall in human history. While it doesn’t meet the exact definition of free fall described earlier as there is air resistance, it is still very close to real free fall as the alternative would be performing the same stunt in an actual vacuum.

The fall lasted 15 minutes as he went over 800 miles per hour which is significantly over the sound barrier.

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