Machines Theory

Understanding Free Fall

The sole force acting on an object or body during free fall is gravity. This external force on the object causes acceleration, which accelerates the object’s motion. Free-fall motion is therefore sometimes referred to as acceleration due to gravity in ordinary speech. Because the gravitational force, rather than the pull, is downward and has a constant value, the acceleration in this motion is constant. And when a body is under zero gravity, the situation will still be true.

Free fall

Today, you will learn the definition, examples, formulas, and some calculations for free fall.

Let’s get started.

What is free fall

In mechanics, “free fall” refers to a state in which a body is free to move in any direction while subjected to gravity. For instance, the planets are falling freely within the Sun’s gravitational field. A body is said to be in freefall when it only moves in relation to the Earth’s gravity. An external force exerted on the ball will cause its motion to accelerate. The term “acceleration due to gravity” is also used to describe this free-fall acceleration.

Another crucial category of free-fall problems is projectile motion. The fact that the acceleration due to gravity is constant across all masses is a very unique and fascinating property. Before Galileo Galilei, this was far from a self-evident fact. That was due to the fact that air resistance has the tendency to slow down the acceleration of lighter objects, so gravity isn’t the only force at play whenever anything is falling. When comparing the rate of fall of a stone and a flower, it’s an observation that we’ve all noticed.

Galileo carried out these brilliant tests at the “leaning” Tower of Pisa, demonstrating that gravitational acceleration is independent of the mass of the objects by dropping masses of various weights from the tower’s summit. Free-fall problems have the assumption of the absence of air resistance. However, in reality, an object in free fall encounters some resistance from the Earth’s atmosphere. Additionally, as the falling object comes into contact with particles in the air, some of its kinetic energy is converted to thermal energy. Because of this, there is “less motion” or a more gradual increase in the downward velocity.

Read more: Understanding gravitational energy

Examples of Free Fall

Below are a few examples of free fall:

Free fall
Apple fruits falling from a tree
Bungee jumping
Bungee jumping
Leafs falling from a tree
Leafs falling from a tree
Gunfire
Bullet shells falling after gunfire
Skydiving
people skydiving
Projectile motion
A basketball being thrown, which ends up falling freely

Read more: Understanding distance and displacement

Free fall formulas

Below are the formulas for free fall.

  1. v = gt
  2. h = ½ gt²
  3. v² = 2gh

Where,

h stands for height covered.
v stands for final velocity.
g stands for acceleration due to gravity.
t stands for the time taken.

Read more: Understanding Speed and velocity

Calculations

Here are a few free fall examples along with the solutions.

Example 1

If the mass of a body is 2 kg and falls on the ground after 5 seconds, calculate the height covered by the body?

Solution

We should start by laying out the values we need first.

  • Time (t) = 5 sec
  • Taking (g) for 9.8m/s²

For us to calculate the height covered by the body, we’re going to be using the equation h = ½ gt².

Substituting the values into h = ½ gt²,

h = ½ gt²

h = ½ × 9.8 ×5²

h = 4.9 × 25

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h = 122.5 m

The total height the body covers is 122.5 m.

Read more: Understanding kinematics

Example 2

A cotton ball falls after 4 seconds and an iron ball falls after 7 seconds. Calculate which of the objects falls with a higher velocity.

Solution

We should start by laying out the values we need first.

  • Time of falling of the cotton ball = 4 seconds
  • Time of falling of the iron ball      = 7 seconds
  • Taking (g) for 9.8 m/s²

For us to calculate the velocity for both the cotton ball and the iron ball, we’re going to be using the equation v = gt.

Cotton ball velocity

v = gt

v = 9.8 × 4

v = 39.2 m/s

Iron ball velocity

v  = gt

v = 9.8 × 7

v = 68.6 m/s

Based on our calculations, we can see that the velocity with which the iron ball falls is higher than that of the cotton ball.

Read more: Understanding acceleration

Frequently Asked Questions (FAQs)

What is it meant by “free fall”?

“Free fall” refers to a state in which a body is free to move in any direction while subjected to gravity. For instance, the planets are falling freely within the Sun’s gravitational field. A body is said to be in freefall when it only moves in relation to the Earth’s gravity.

What are the formulas for free fall?

  • v²= 2gh.
  • v = gt.

What causes free fall?

Only when there are additional forces at play will light objects accelerate more slowly than heavy ones. An object may be falling at this time, but it is not falling freely. When just gravity is acting on an object, free fall occurs.

What are the cases of free fall?

  • A fruit or a flower falling from a tree.
  • Bungee jumping
  • Bullet shells fall after gunfire.
  • An object rolling down the hill.
  • A person skydiving.
  • An object undergoing a projectile motion

What is the speed of freefall?

The final velocity of a human body in a stable, belly-to-earth position is roughly 200 km/h (about 120 mph). The terminal speed in a steady, free-flying, head-down position is between 240 and 290 km/h (around 150-180 mph).

Does mass matter in free fall?

The size, mass, and shape of the object are not relevant when describing its motion. Due to this, all objects fall at the same rate, regardless of their size, shape, or weight.

Which falls first, a ball or a feather?

The opposing force of air resistance is what causes the feather to fall more slowly. The feather and air come into contact with each other more frequently than the bowling ball does. Because of this, it descends to the ground MUCH MORE SLOWLY than a bowling ball.

Do heavier objects fall faster?

Additionally, if two identically shaped and weighted objects are present, the heavier (larger) one will fall faster due to the fact that as an object gets bigger, the drag force to gravitational force ratio is smaller.

What falls faster, a brick or a penny?

If we neglect air friction, heavier items fall as quickly (or slowly) as lighter objects. Air friction can influence things, but it does it in a complicated way. There is a constant gravitational acceleration for all objects.

What falls faster, a brick or a feather?

A brick would suddenly fall to the ground and do so very fast. The speed would increase rapidly. whereas a feather would actually float on air. The feathers you have on Earth would simply float around.

That concludes this article, which covered the definition, examples, formulas, and calculations for free fall.

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