Now that you have learnt how to resolve the initial velocity into horizontal and vertical components, it is possible to tackle projectile motion problems where the particle is projected at any angle. When considering the motion of a particle projected at an angle, the vertical and horizontal components are independent of each other, and therefore the calculations for vertical and horizontal movement can be considered separately.
Projection at any angle
When a particle is projected at an initial velocity U at an angle α above the horizontal, resolve the initial velocity into components. The horizontal and vertical motion can then be considered separately.
Horizontal motion
There is no acceleration in the horizontal direction as the only acceleration is vertical, (acceleration due to gravity). Therefore, the horizontal component of a projectile is considered to have constant velocity. The equation s=vt is used. The horizontal component of the initial velocity is Ucosα.
Vertical motion
Acceleration due to gravity is9.8m.s−2, and so the formulae for constant acceleration can be used in the vertical direction. The vertical component of the initial velocity is Usinα. When a projectile reaches its greatest height, the vertical component of the velocity is 0.
Equations
description
equation
Horizontal motion is modelled as having
constant velocity (a=0).
s=vt
Vertical motion is modelled as having
constant acceleration due to gravity,
so the constant acceleration formulae can be used.