We have already discussed about a particle exhibiting motion in one-dimension. In such cases, we only observed the movement of the particle and whose position and direction of motion could be described by only one space coordinate. Now, we will learn about Projectile Motion, which is a two-dimensional motion and requires two space coordinates to describe the position and direction of motion of the particle.
Projectile Motion
Definition: Any particle falling only under the influence of gravity is termed as projectile and the motion followed by such particle is called projectile motion. Examples: a ball kicked by a player, stone thrown from the top of a large cliff, etc.
The path followed by the projectile during its entire motion is termed as its trajectory. During the whole journey, the particle is acted by a constant downward acceleration equal to the acceleration due to gravity of the Earth. This acceleration only affects the vertical component of velocity of the projectile. The horizontal component of velocity of the projectile remains constant throughout the motion.
In the above picture, we can analyse the motion of the ball. When the ball is kicked initially, it has larger force due to which it continues to ascend height. However, with time, its velocity decreases due to constant retardation offered by the acceleration due to gravity. After certain interval of time, the ball cannot ascend any further and stops for an instant. Then, it follows the direction of acceleration due to gravity and starts falling downwards. With time, it finally reaches the ground on the same level from which it was thrown upwards.
Features of Projectile Motion
- The horizontal component of velocity remains constant throughout the motion.
- The projectile is acted by a constant downward acceleration equal to acceleration due to gravity.
- At the highest point of trajectory, velocity and acceleration are perpendicular to each other.
- The time taken by parabola to ascend to the maximum height is equal to the time taken to descend from the maximum height.
- The weight of a body is minimum at the highest point in the trajectory.