I have a question about a projectile motion problem. So the background info of this problems is that a quarterback is throwing a football to a receiver who's running with constant v_r and he's now D distance away from the quarterback. The quarterback thinks that it should be thrown at angle theta and the receiver must catch the ball at t_c. The ball is thrown and caught at the same height. Now, I have to find v_0y in terms of t_c and g I just thought it was vsintheta.... how do you find it that way? Is it v = 1/2gt^2?? and the v_0x, I have to find in terms of D, t_c, and v_r..... I am totally lost here... please help!