This PPT covers projectile motion of an object in a very systematic and lucid manner. I hope this PPT will be helpful for instructors as well as students.
Size: 2.21 MB
Language: en
Added: Aug 28, 2018
Slides: 30 pages
Slide Content
PROJECTILE MOTION
Projectile motion Projectile motion is a motion in which an object is thrown near the earth’s surface, and it moves along the curved path under the action of gravity only.
Motion of a snow boarder descending from a slope
Motion of a rider performing a bike stunt
Motion of water jets coming out from nozzles
Assumptions used in projectile motion The effect due to air resistance is negligible. The effect due to curvature of the earth is negligible. The effect due to rotation of the earth is negligible. The acceleration due to gravity is constant over the range of motion.
Idealized model of projectile motion
Projectile Any object which is projected in the air is called as projectile. Projectile
Point of projection The point from which the object is projected in air is called as point of projection. Point of projection
Velocity of projection The velocity with which an object is projected in air is called as velocity of projection. Velocity of projection
Angle of projection The angle with the horizontal at which an object is projected in air is called as angle of projection. Angle of projection
T rajectory The parabolic path followed by a projectile in air is called its trajectory. Trajectory
Time of flight Time taken by the projectile to cover the entire trajectory is called as time of flight. Time of flight
Maximum height of projectile It is the maximum vertical distance travelled by the projectile from the ground level during its motion. Maximum height
Horizontal range of projectile It is the horizontal distance travelled by the projectile during entire motion. Horizontal range
Is horizontal and vertical motions are interdependent? Both pink and yellow balls are falling at the same rate. Y ellow ball is moving horizontally while it is falling have no effect on its vertical motion. It means horizontal and vertical motions are independent of each other.
Analysis of projectile motion Motion diagram of a kicked football
Important conclusion Projectile motion is a combination of two motions: Horizontal motion with constant velocity Vertical motion with constant acceleration
Equation of trajectory The horizontal distance travelled by the projectile in time ‘t’ along -axis is, The vertical distance travelled by the projectile in time ‘t’ along -axis is, Substituting the value of ‘t’ from eq.(1) in eq.(2) we get, This is the equation of trajectory of a projectile. Thus is a quadratic function of . Hence the trajectory of a projectile is a parabola. As , and are constant for a given projectile, we can write
Equation for time of flight The vertical distance travelled by the projectile in time ‘t’ along -axis is, For symmetrical parabolic path, time of ascent is equals to time of descent. For entire motion, and This is the equation for time of flight.
Equation for horizontal range The equation of trajectory of projectile is given by, This is the equation for horizontal range. For a given velocity of projection the range will be maximum when , For entire motion, and Thus range of the projectile is maximum if it is projected in a direction inclined to the horizontal at an angle of .
Two angles of projection for the same horizontal range The equation for horizontal range is given by, Replacing by , From eq. (1) & (2) we say that , Thus horizontal range of projectile is same for any two complementary angles i.e. and
Equation for maximum height The third kinematical equation for vertical motion is , At maximum height: This is the equation for maximum height. Case-1: Angle of projection is . Case-2: Angle of projection is .