1.2 Projectile Motion

Sometimes we can have the horizontal and vertical components of motion in a question.

Horizontal motion:

If you ignore air resistance there will be no forces acting horizontally. Therefore, the object will move at a constant speed. We only need to use displacement, initial velocity and time.

Which means we only need to use the equation:

X= Ut

Vertical motion:

The force of gravity causes acceleration at a constant value of 9.81ms-2. There fore we can use the kinematics equations:

X = ut + ½ at² or v² = u² + 2aX

The best way to approach these questions is to make a table of the vertical and horizontal components, like this: