Preloader
  • By koushiadmin
  • (0) comments
  • June 8, 2025

Projectile motion Theory

Projectile motion: The two dimensional motion of the body under the action of gravity is called projectile.

Let us consider, a particle is thrown with initial velocity  at an angle θ with horizontal direction. The horizontal and vertical component of velocities are respectively ux = ucos and uy = usin.

Velocity: Let us consider vx and vy are the horizontal and vertical component of velocities at point P(x, y). As gravitational acceleration (g) acts downwards, then horizontal component of acceleration is gcos90= 0.

So, vx = ux = ucos ——–(1)

And vy = uy – gt = usin – gt ——–(2)

So, the magnitude of velocity of particle at point P is v = ——–(3)

Displacement: Let us consider, the coordinates of point P is (x, y).

So, x = uxt = utcos ——–(4)

And y = uyt – gt2 = utsingt2 ——-(5)

The trajectory of the motion is y = usin() – g()2

 y = xtang()2 ——–(6) This is the equation of parabola.

Maximum height: At point A, particle is at maximum height. At point A, the velocity of the particle is along the tangent. So, vy= 0.

Therefore, usin – gt = 0 [using equation (2)]

∴ t =

Substituting the value of t in equation (5) we get, maximum height

H = usin() – g()2

∴ H =  ——— (7)

Time of flight: The total time taken by the particle during its motion is T. During time of flight then the net displacement along y axis is 0. From equation(5) we get, uTsingT2 = 0

∴T =   ——–(8)

Range: The maximum horizontal distance travelled by the body is called range.

Range R = uxT = ucos(  ) = .

Example: A ball is projected horizontally with speed v from the edge of a stair as shown in the figure. If the height of each step of stair is h and width is l then at which step of the stair the ball will touch?

Let us considered, the ball will touch nth step of the stair at time t.

The horizontal distance travelled by the ball is x = nl = vt or, t =  —— (i) [horizontally acceleration a = gcos900 = 0]

The vertical distance travelled by the ball is y = nh =  ——- (ii)

[the vertical component of initial velocity is ucos900 = 0]

From equation (i) and (ii) we get, nh =

Or, n = .

koushiadmin

previous post next post

Leave a comment

Your email address will not be published. Required fields are marked *

contact info

subscribe newsletter

Subscribe to get our Latest Updates

Get updates On New Courses and News

© 2018 – 2025 Koushi All Rights Reserved