## Projectile Motion – Class 11 | Chapter – 4 | Physics Short Notes Series PDF for NEET & JEE

Projectile Motion: Projectile motion refers to the motion of an object that is projected into the air and then moves under the influence of gravity alone. Examples of projectiles include a ball thrown in the air, a bullet fired from a gun, or a rocket launched into space. The motion of projectiles can be analyzed using the laws of motion and the principles of kinematics. The motion of a projectile can be broken down into two components: horizontal motion and vertical motion. The horizontal motion is constant and unaffected by gravity, while the vertical motion is accelerated due to the force of gravity acting on the projectile.

## Equations of Projectile Motion

The equations of motion for a projectile launched at an angle θ with an initial velocity v0 can be derived using kinematic equations:

x = v0 cos θ t y = v0 sin θ t – 1/2 g t2

where x and y are the horizontal and vertical position coordinates of the projectile at time t, v0 is the initial velocity, θ is the launch angle, and g is the acceleration due to gravity (usually taken to be 9.8 m/s2).

Using these equations, we can calculate the range, maximum height, time of flight, and other characteristics of the projectile motion. For example, the range is the horizontal distance traveled by the projectile before it hits the ground and is given by:

R = v02 sin 2θ / g

The maximum height reached by the projectile is given by:

hmax = v02 sin2 θ / (2 g)

The time of flight is given by:

tflight = 2 v0 sin θ / g

## Types of Projectile Motion

There are two main types of projectile motion: horizontal projectile motion and oblique projectile motion.

• Horizontal Projectile Motion: In this type of motion, the projectile is launched horizontally from a certain height above the ground. The angle of launch is 0 degrees, which means that the initial velocity of the projectile has only a horizontal component, and there is no initial vertical velocity. Due to the force of gravity, the projectile follows a parabolic path and hits the ground after a certain time. Examples of horizontal projectile motion include a ball rolling off a table or a rock thrown horizontally off a cliff.
• Oblique Projectile Motion: In this type of motion, the projectile is launched at an angle with respect to the horizontal. The angle of launch is typically between 0 and 90 degrees, and the initial velocity of the projectile has both horizontal and vertical components. Due to the force of gravity, the projectile follows a curved path, and its trajectory is a parabola. The range, maximum height, and time of flight of the projectile depend on the angle of launch and the initial velocity. Examples of oblique projectile motion include a ball thrown at an angle, a rocket launched into space, or a cannon firing a projectile.

## Properties of Projectile Motion

Projectile motion has several important properties that can be analyzed and predicted using the laws of physics. Here are some of the key properties of projectile motion:

• Trajectory: The trajectory of a projectile is the path it follows through the air. Due to the force of gravity, the trajectory of a projectile is a parabolic curve.
• Range: The range of a projectile is the horizontal distance it travels before hitting the ground. The range depends on the initial velocity of the projectile and the angle of launch.
• Maximum Height: The maximum height of a projectile is the highest point it reaches in its trajectory. The maximum height depends on the initial velocity of the projectile and the angle of launch.
• Time of Flight: The time of flight of a projectile is the amount of time it spends in the air before hitting the ground. The time of flight depends on the initial velocity of the projectile and the angle of launch.
• Velocity: The velocity of a projectile changes continuously throughout its trajectory. At the highest point of its trajectory, the projectile has zero vertical velocity, while its horizontal velocity remains constant.
• Acceleration: The acceleration of a projectile is constant and equal to the acceleration due to gravity (9.8 m/s2) in the downward direction.

## Importance of Projectile Motion

Projectile motion is an important concept in physics and engineering because it helps us understand and predict the motion of objects that are thrown, launched, or propelled into the air. Here are some specific reasons why projectile motion is important:

• Ballistics: Projectile motion is used in ballistics to study the motion of bullets, shells, and other projectiles fired from guns and artillery. By understanding the trajectory of a projectile, ballisticians can optimize the design of weapons, predict their accuracy and range, and ensure their safety and effectiveness.
• Sports: Projectile motion is also important in sports such as football, soccer, and basketball, where players must throw or kick a ball with a certain velocity and angle to achieve their desired outcome. By understanding the physics of projectile motion, athletes can improve their performance and coaches can develop better strategies and training programs.
• Aerospace Engineering: Projectile motion is crucial in aerospace engineering, as it is used to predict the motion of spacecraft and other objects launched into space. By analyzing the trajectory of a spacecraft, engineers can optimize its launch profile, calculate its trajectory, and ensure its safe arrival at its destination.
• Physics Education: Projectile motion is a fundamental concept in physics education, as it is used to introduce students to the laws of motion, kinematics, and gravity. By studying projectile motion, students can develop their analytical and problem-solving skills and gain a deeper appreciation for the physical world around them.

 JOIN OUR TELEGRAM CHANNELS Biology Quiz & Notes Physics Quiz & Notes Chemistry Quiz & Notes