A cannon fires a shell straight upward; 2.2 s after it is launched, the shell is moving upward with a speed of 20 m/s. Assuming air istance is negligible, find the speed (magnitude of velocity) in meters per second of the shell at launch and 5.1 s after the launch. (a) at launch 40.56 X Consider which constant acceleration relation will allow you to find the final speed with the given information. Also, be careful of signs and directions. If the acceleration due to gravity is downward and the final velocity is upward, what should their signs be? m/s (b) 5.1 s after the launch 62.12 You can either use the initial velocity at launch (from part a) and total time, or the initial velocity after the first time interval and the difference in time between the total time and first time interval, to find the final velocity. Like part (a), consider which constant acceleration kinematic relation is appropriate, and be careful of the signs for initial velocity and acceleration. Remember that speed is the magnitude of velocity, and therefore a positive number. m/s