Projectiles · Year 13

In Year 13 you learn: projectiles.

A projectile is anything thrown or launched that then moves under gravity alone. The key idea is to split the motion. Horizontally, the velocity never changes. Vertically, it accelerates downwards at g. Both parts share the same time.

Key facts

• Components of the launch velocity: horizontal u cos θ and vertical u sin θ.
• Horizontally: constant velocity, x = (u cos θ)t.
• Vertically: SUVAT with a = −g. So y = (u sin θ)t − 1/2gt^2, and the vertical velocity is u sin θ − gt.
• Speed = √(H^2 + V^2), where H and V are the horizontal and vertical velocities. The angle to the horizontal is tan⁻¹(V/H).
• Modelling assumptions: no air resistance, the object is a particle, and g is constant.