Thanks for your help So, if I wanted to calculate the vertical component of time, I know that.. S = 18tan30 U = ? V = 0 (final velocity) A = -9.81ms-² T = ? Which leads me to the problem that no equation of motion tends for only the 4 variables of displacement, final velocity, acceleration to give time I’ve got as far as splitting the horizontal component into half to give… So from this I should be able to calculate the initial velocity, as I have the same as before S = 18tan30 U = ? V = 0 (final velocity) A = -9.81ms-² T = ? So, using v² = u² + 2as I can rearrange to find U² = 2as – v² ∴ u² = 2(9.81)(18tan30) – 0² u² = square roof of 203.9 u = 14.3ms-² Although I know this is wrong. Because this velocity only gives a range of 18 meters, and if I was to double the initial velocity it gives a range of more than double EDIT: I could use the value derived for initial velocity in the vertical plane to calculate the T in the vertical. However, the initial velocity is derived and I don't want to carry that error forward, because I'm not happy that that is the correct value for initial velocity. (Or is this initial velocity ONLY in the vertical plane?)