An object that is thrown vertically upward is also a projectile (provided that the influence of air resistance is negligible).

An object dropped from rest is a projectile (provided that the influence of air resistance is negligible).

There are a variety of examples of projectiles. Thus, Lesson 2 of this unit is devoted to understanding the motion of projectiles.Ī projectile is an object upon which the only force acting is gravity. The most common example of an object that is moving in two dimensions is a projectile. Now in this unit we will apply both kinematic principles and Newton's laws of motion to understand and explain the motion of objects moving in two dimensions. In Unit 2 of the Physics Classroom Tutorial, we learned how Newton's laws help to explain the motion (and specifically, the changes in the state of motion) of objects that are either at rest or moving in 1-dimension. Hence the path of a projectile projected at some angle with the horizontal direction is a parabola.In Unit 1 of the Physics Classroom Tutorial, we learned a variety of means to describe the 1-dimensional motion of objects. The position of the projectile along the Y-axis at any time t is given by Initial velocity along vertical, u x = u sin θ The velocity of the projectile along the vertical goes on decreasing due to the effect of gravity The position of the projectile along the X-axis at any time t is given by Initial velocity along the horizontal, u x = u cos θĪcceleration along the horizontal, a x = 0 Motion along horizontal direction: If we neglect the friction due to air, then the horizontal component of the velocity i. Let that any time t, the projectile reaches the point P, so that its distances along the X and Y-axis are given by x and y respectively. The velocity of projection of the projectile can be resolved into the following two componentsĪs the projectile moves, it covers distance along the horizontal due to the horizontal component u cos0 of the velocity of projection and along vertical due to the vertical component u sin0. Let OX be a horizontal line on the ground and OY be a vertical line: O is the origin for X and Y-axis.Ĭonsider that a projectile is fired with velocity u and making an angle θ with the horizontal from the point ‘O’ on the ground

The entire trajectory is near the surface of the earth.

The effect due to the curvature of the earth is negligible.

To study the motion of a projectile we assume that: Projectiles can be thrown in various ways on level ground, from a high tower to ground, from an airplane etc.

The force of gravity continuously affects the vertical components so the vertical motion is a uniformly accelerated motion.

The horizontal motion is a uniform motion. Thus, in projectile motion the horizontal component of velocity remains unchanged throughout the motion. If acceleration in a particular direction is zero then velocity in that direction remains the same.

The velocity of the projectile can be resolved into two mutually perpendicular components the horizontal component and the vertical component.

These two motions take place independently of each other.

The motion of a projectile is a two-dimensional motion so, it can be discussed in two parts.

Projectile motion is a planar motion is which at least two position coordinates change simultaneously. Velocity and Acceleration in Projectile Motion

A missile deployed from a military aircraft from level flight.

A jet of water ejecting from a hole near the bottom of the water tank.

A piece of stone is thrown in any direction.

A javelin or hammer was thrown by an athlete.

The object projected into space or air is called a projectile and the path followed by the projectile is called a trajectory.įollowing are a few examples of the projectiles: The only force of significance that acts on the object is gravity, which acts downward. Projectile motion is a two-dimensional motion in which an object or particle is thrown upward at an angle to the horizontal and it moves along a curved path due to the action of gravity.

Projectile motion physics