1. The problem statement, all variables and given/known data For a physics project, i need to answer a bunch of questions after conducting an experiment with projectile motion. I have answered most of them. The questions with the work shown are here: http://i.imgur.com/JmYPMC9.png I cannot answer number 10 and 11, because I don't have the values for Force or acceleration. However, I'm pretty sure there's a way to do it because this is a project that people have done before. 10. What is the horizontal force you exerted on the ball? 11. What is the amount of time you were in contact with the ball when throwing it? I'm also not sure if question 9 is correct about Work. I figured W = KE, but I'm not sure if that's correct. 2. Relevant equations W = Fd = mgh = change in KE Impulse (J) = p' - p = mv' - mv = Ft 3. The attempt at a solution W in the horizontal direction = F* d = F (15.5m) = (J/t)(15.5m) = (19.705 Nm)/t)(15.5m)... W in vertical direction = mgh = (.055kg)(9.81 m/s^2)(1.226 m) = .66 J Horizontal Force = m * a = (.055kg)(0 m/s^2)... except this does not seem right. So i think I have to find this value from impulse which is Ft. I do not have time. Amount of time in contact with the ball... I can only think of getting this from impulse. But i do not have the force.