1. The problem statement, all variables and given/known data 1) A rocket traveling at 155 m/s is accelerated at a rate of -31.0 m/s^2. a. how long will it take before the instantaneous speed is 0 m/s. b. how far will it travel during this time? c. what will be it's velocity after 8.00 s? 2. Relevant equations i have all of the following formulas: vf = vi+at d = (vf+vi)/2 x t d = (vi)(t) + 1/2(a)(t)^2 vf^2 = vi^2 + 2(a)(d) i don't think any of these equations will work for the problem. i really need help deciding which one of these to use, if any of these are even usable for the problem. do i make the initial velocity 0 m/s and the final velocity 115 m/s? and then solve for time? i really have no idea. i'm just assuming that's what i'd do. one more... 1. The problem statement, all variables and given/known data 2) one such gun can give a small object a velocity of 3.5 km/s moving it through only 2.0 cm. a. what acceleration does the gun give this object? b. over what time interval does the acceleration take place? 2. Relevant equations do i use 2.0 cm as the displacement, and make initial velocity 0 km/s and final velocity 3.5 km/s? or am i completely wrong? thank you so much for any help!