College Physics with MasteringPhysics 7th Edition by Jerry Wilson,Anthony Buffa,Bo Lou

Exercise 24

Let's investigate a possible vertical landing on Mars that includes two segments: free fall followed by a parachute deployment. Assume the probe is close to the surface, so the Martian acceleration due to gravity is constant at 3.00 m/s 2. Suppose the lander is initially moving vertically downward at 200 m/s at a height of 20 000 m above the surface. Neglect air resistance during the free-fall phase. Assume it first free falls for 8000 m. (The parachute doesn't open until the lander is 12 000 m from the surface. See Fig.) (a) Determine the lander's speed at the end of the 8000-m free-fall drop. (b) At 12 000 m above the surface, the parachute deploys and the lander immediately begins to slow. If it can survive hitting the surface at speeds of up to 20.0 m/s, determine the minimum constant deceleration needed during this phase. (c) What is the total time taken to land from the original height of 20 000 m

FIGURE Down she comes See Exercise.