hope this help
For normal projectile question, it will state an object is thrown upwards at an angle of projectile.
1. Horizontal velocity, u cosθis always constant because there is no gravity acceleration.
Hence, s = vt, where v = u sinθ
2. Vertical velocity increases as the gravity acceleration decreases. Hence the acceleration, a = - g = -9.81 ms-1
3. When doing calculations, divide the motion into vertical and horizontal component. There is only one formula involve for horizontal speed as mentioned above.
4. Time is the same for both components. If you counted v (θ is given), you can count u sin θ.
5. The vertical component can be count using normal motion equation.
(eg: v = u+at, s = ut +?at2 ). s for vertical motion is the height.
6. Usually s and θ will be given, then the question can be solved using the above sequence.
7. If the question state ?projected horizontally?, that means initial velocity for vertical component is zero.
Hence for vertical, v = u+at , u = 0, a = 9.81