I have a question about this classical mechanics application. Given is a point with mass m and speed v0. It gets shot from the ground under an angle alpha. Wanted is the path of this projectile. This is a two dimensional example so I need to find the motion equation. I know that m*x(double dot) = Fx = 0 and m*y(double dot) = Fy = -m*g so x(double dot) = 0 and y(double dot) = -g The initial speed is given by : v0 = v0*cos(alpha)*1x + v0*sin(alpha)*1y (vectorial notation) Then they say that the first integration regarded to t gives: x(dot) = constant = x(dot)(0) = vo*cos(alpha) and y(dot)(t) = -g*t + constant = -g*t + v0*sin(alpha) I don't see how they come to this result. Can someone explain this? Further they say that the second integration regarded to t gives: x(t) = (v0*cos(alpha))*t y(t) = -1/2*g*t² + (v0*sin(alpha))*t Then they say that the path of the object is in the x,y plane with equation y = F(x) Now they ask me to find that F(x). They say you can do it by elimination of the variable t (t= x/(v0*cos(alpha))) Can anyone explaine me how they find this value for t and how this elimination procedure works? Many thanks in advance!