1. The problem statement, all variables and given/known data A two stage rocket is launched with an average acceleration of +4 m/s/s. After 10 seconds, a second stage is activated and the rocket's acceration is now +6 m/s/s. Part A: Find the vertical displacement of stage one of the rocket, before accleration changes to 6. Part B: Find the final speed after 10 seconds of motion. Part C: The second stage is activated, find the total height the rocket ascends (its highest point) before it starts to travel back to earth. Part D: Find the displacement traveled by the second stage only. 2. Relevant equations Vf = Vi + a[tex]\Delta[/tex]t [tex]\Delta[/tex]y = Vi[tex]\Delta[/tex]t + 0.5a([tex]\Delta[/tex]t)^2 (Vf)^2 = (Vi)^2 + 2a[tex]\Delta[/tex]y 3. The attempt at a solution For Part A I calculated displacement with [tex]\Delta[/tex]y = Vi[tex]\Delta[/tex]t + 0.5a([tex]\Delta[/tex]t)^2. y was my unknown variable and my Vi was 0, my t 10 seconds, and my a +4. I got 200meters. For Part B I calculated the first stage's final speed by using the equation Vf = Vi + a[tex]\Delta[/tex]t. I had a Vi of 0, an accleration of +4 and a t of 10. My velocity final was +40 m/s. As far as part c goes I plugged everything into (Vf)^2 = (Vi)^2 + 2a[tex]\Delta[/tex]y this time I had a velocity initial as +40 [part b] and i used 0 as my velocity final because i was solving for the peak. However, my negative signs got messed up. Here's where I need help. Am I on the right track??