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Horizontal Motion

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Last updated date: 22nd Mar 2024
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Introduction to Projectile

A projectile is when any object is thrown into space with only gravity acting on it. The fundamental force exerted on a projectile is gravity. This isn't to say that other forces don't affect it; it only means that their impact is minor in comparison to gravity. A trajectory is a path that a missile follows. A batted or thrown baseball is also an example of a projectile.


What is Projectile Motion?

When a particle is thrown obliquely near the earth's surface, it takes a curved, constant-acceleration path to the centre of the earth (we assume that the particle remains close to the surface of the earth). The path of such a particle is referred to as a projectile, and its motion is referred to as projectile motion.

In a projectile motion, two separate rectilinear motions occur at the same time:

  • x-axis: Uniform velocity is measured along the x-axis and is responsible for the particle's horizontal (forward) motion.

  • y-axis: Uniform acceleration, which is responsible for the particle's vertical (downward) motion.


Motion of a Projectile

Gravitational forces cause projectiles and satellites to travel in curved courses. We can anticipate their course by considering motion in both horizontal and vertical directions.

Vertical and horizontal movement


The force of gravity controls the vertical motion of a projectile. This indicates that the ball is being acted upon by an imbalanced force, causing it to accelerate downwards. This acceleration is \[9.8 ms^{-2}\] (the gravitational field strength on Earth).


Because the projectile's vertical speed is not constant, any vertical motion estimate must account for the acceleration.

\[a_{v} = \frac{v_{v} - u_{v}}{t}\]


Where,\[ v_{v} \] represents the final vertical speed and \[ u_{v} \] represents the beginning vertical speed.


Horizontal Motion Definition

In physics, the projectile motion is broken into two components: horizontal and vertical. In most cases of projectile motion, the vertical component is due to the action of gravity.


For every object, the gravitational force causes a constant acceleration of 32.2 ft/s2 or 9.8 m/s2 towards the Earth.


Horizontal motion is defined as a projectile motion in a horizontal plane depending upon the force acting on it. For a short distance, the vertical and horizontal components of a projectile are perpendicular and independent of each other.


The horizontal component of the speed of a projectile is constant throughout the flight duration. This is because, after launching the projectile, no horizontal force acts on it. So the projectile travels horizontally at a constant speed. To calculate the distance covered by a projectile, the following equation is used;


Distance = speed × Time


d = vt


Horizontal Motion Physics

To obtain a horizontal motion, a projectile must be launched in a straight line, and not at any angle. The velocity of the projectile varies, but the direction in which a projectile is launched should be perpendicular to the surface of the Earth.


A constant vertical force of gravity acts upon the projectile which does not depend on the horizontal force and is used to launch the projectile. This means that the total time of flight of the projectile will always be the same.


The projectile can be made to travel longer or shorter distances in the same amount of time by changing the initial velocity and the force applied to launch the projectile.


For long-distance travel, like that of a missile, a projectile must be launched at a particular angle, and the horizontal and vertical components must be determined to make the projectile travel a longer distance.


Motion in a plane is also called a motion in two dimensions. Some examples of two-dimensional motions are circular motion and projectile motion. 


For the analysis of two-dimensional projectile motion, m is a reference point taken at the origin of two coordinate axes viz: the X-axis and Y-axis. Projectile motion is one of the best examples of motion in a plane.

  • The horizontal velocity of the ball remains constant while it falls because gravity doesn’t exert any horizontal force.

  • As there is no force, the horizontal acceleration is zero (ax = 0).

  • The ball moves in a steady state to the right at 5 m/sec.


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Horizontal Motion Examples

Some examples of horizontal motion are given below:

  • The motion of the Earth around the sun is horizontal.

  • A boat travelling in a river.

  • A shell fired from a gun.

  • The motion of a billiard ball on the billiard table is horizontal.

  • Throwing a ball or a cannonball is a horizontal motion.


Example of Horizontal Projectile Motion

Suppose you want to calculate the time of flight and the distance travelled by a ball (projectile in this case) thrown from the top of the Eiffel tower with a horizontal speed of 7 m/s.

  1. First, launch the projectile at a horizontal speed of 7 m/s. Change the units if needed.

  2. Calculate the initial height from which the motion of the projectile starts. The upper platform of Eiffel's tower is 276 m (906 ft) above the ground.

  3. The calculator of horizontal projectile motion shows the tile of flight, distance travelled, and trajectory. 

It can be found out that it takes around 7 seconds for the ball to reach the surface or ground. The horizontal displacement will be approximately 48.56 m.


Remember that the tools of a horizontal projectile calculator are really flexible. Just type any two known values in it and the horizontal projectile motion calculator will calculate the remaining parts. 


For example, you can calculate the velocity required to throw a ball from the height such that it reaches a horizontal distance of 100 m from the base of the tower.


Horizontal Motion Procedure


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  • Drop two stones vertically from the same height and at the same time, one from each hand. Listen when the stones hit the ground. They have to land on the surface of the ground at the same time.

  • Repeat the same experiment, but this time, release one stone in a little horizontal motion by moving one of your hands sideways as you let the stones go.

  • Repeat and throw both the stones out sideways with different velocities.

  • Try it with stones of unequal sizes.

  • Try dropping both the stones from an open window or a staircase.

  • Try to increase the horizontal speed of the stone.

  • We could record the motion of the stones using a video camera.


Teaching Notes

  • The objects of different masses, when launched with the same vertical acceleration, fall at the same time.

  • The fall of a stone from a particular height takes the same time whether or not it has a horizontal motion.

  • The independence of the horizontal component and vertical component of motion enabled Galileo to examine the horizontal motion of projectiles that are free from any accelerating force.

FAQs on Horizontal Motion

1. What are the two kinds of Projectile Motion?

There are two independent rectilinear motions:

  1. Along the x-axis: The axis of uniform velocity, which is responsible for the horizontal (forward) motion of the particle.

  2. Along y-axis: The axis of uniform acceleration, which is responsible for the vertical (downwards) motion of the particle.

2. What is the formula for Horizontal Distance?

Horizontal distance is calculated by using the formula, X = V * t. 

The vertical distance from the ground is calculated by the formula y = – g * t²/2.

Where,

g = acceleration due to gravity.

h = elevation.

3. How far will the ball travel horizontally?

If a ball is thrown horizontally at a velocity of 30 m/s, then after 1 second, it will have travelled 30 metres, after 2 seconds, it will have travelled 60 metres, after 3 seconds, it will have travelled 90 metres, etc. The distance travelled by the ball relies on time.

4. Is horizontal motion constant?

A projectile's horizontal velocity is constant (it never changes). There is a vertical acceleration induced by gravity; it is 9.8 m/s/s, down. A projectile's vertical velocity changes by 9.8 m/s every second, and its horizontal motion is independent of its vertical motion.

5. What is the difference between vertical and horizontal?

We use the terms vertical and horizontal in geometry to describe standing and sleeping, respectively.


Because vertical is the total opposite of horizontal, it refers to anything that forms a 90-degree angle (right angle) with the horizontal or horizon.

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