Master Advanced Physics
(For all Top Exams)
PROJECTILES - 1
Projectiles in Physics are simply bodies that are thrown up OR DOWN AND HAVE 2 DIMENSIONAL MOTION and their behaviours, mathematically or precisely.
When a body is thrown up at an angle to the horizontal, then there are two MOTIONS.
First, the body is moving according to its initial VELOCITY GIVEN.
And second, the body is ALSO AT EVERY MOMENT, under the influence of Gravity, more precisely acceleration due to gravity.
So there are two motions within the body. And each motion can be studied separately as equations and then both compared and resolved.
THIS is the technique used. It is as if each motion is independent OF THE OTHER MOTION.
So there are mainly two ways there can be a projectile, or a body can be projected basically in our topic.
As shown, a body can be
1) Projected at an angle
2) Or a body can be thrown from a height horizontally.
We have to derive equations for these two basic types of motion.
We have a few other special types which we will see after we have considered these two thoroughly.
Body projected horizontally from a height
Here Projectile an object is thrown with an initial velocity u horizontally and it has two motions
Motion due to its initial velocity--- is uniform velocity u as air resistance is considered negligible. So u = R/T ---Eq 1
R = range, distance covered and T= time of flight
Motion due to gravity --- here in the vertical direction
initial velocity = 0
final velocity = v (say)
Acceleration = 9.8 m/s = g
s= Height = H , T = time of fight , V= gT – Eq- 2 , H= ½ gT2 – Eq- 3
V2 = 2gH – Eq 4 So
Time of flight = root of 2H /g
Horizontal range = u Root of 2H/g