Meriam, Kraige & Bolton — Kinetics of Particles: Problem 3_149

3/149 The 15 200-kg lunar lander is descending onto the moon’s surface with a velocity of 2 m/s when its retro-engine is fired. If the engine produces a thrust \(T\) for 4 s which varies with time as shown and then cuts off, calculate the velocity of the lander when \(t = 5\) s, assuming that it has not yet landed. Gravitational acceleration at the moon’s surface is 1.62 m/s\(^2\).