1. The problem statement, all variables and given/known data What is the velocity of a rugby ball 3.0s after it is kicked vertically upwards with a speed of 16m/s? Give your answer to 2 s.f. 2. Relevant equations SUVAT 3. The attempt at a solution s = ? u = 16 v = ? a = g = 9.8 t = 3 Erm... v = u + at? 16 + 9.8 x 3 = 45m/s. Incorrect, try again. ...aha! Ball was kicked vertically up. Acceleration is going to be acting against. Not today, physics! 16 - 9.8 x 3 = -13m/s. Incorrect, try again. Huh. Well, it might be a case of direction. Let's try plain 13m/s. Incorrect, try again. Okay, let's work out the displacement so we can try v = √2gs. s = 16 x 3 - 0.5 x 9.8 x 3^2 = 3.9m. Nice round number! Must be on to something. v = √2 x 9.8 x 3.9 = 8.7m/s. Incorrect, try again. Wait, I'm a doughnut. That's just for free fall. I have a u value. So it's going to be v = √u^2 + 2as. √16^2 + 2 x 9.8 x 3.9 = 18m/s. Incorrect, try again. Uh. Oh, g would still be negative. This has got to do it. √16^2 - 2 x 9.8 x 3.9 = 13m/s. I'm done. SOS.