A skydiver of mass jumps from a stationary balloon at a high altitude where the…
PHYSICS · Multi-part · CBSE · Physics · Laws of Motion · Laws of Motion
Problem
A skydiver of mass 80kg jumps from a stationary balloon at a high altitude where the acceleration due to gravity is 9.5ms−2. During the first part of the descent the skydiver quickly reaches a terminal speed of 60ms−1 while falling feet first. After several seconds at terminal speed, the skydiver deploys a parachute that immediately increases the upward drag force to 1.3×103N.
Neglect the mass of air the skydiver moves through.
(a) While the skydiver is descending at the terminal speed of 60ms−1, calculate the magnitude of the drag force acting on the skydiver. Explain how the value you obtain is consistent with the definition of terminal speed.
(b) Immediately after the parachute opens, determine the skydiver’s acceleration in both magnitude and direction. Show all calculations clearly.
(c) For each of the following phases—(i) initial free fall before reaching terminal speed, (ii) steady descent at terminal speed, and (iii) the instant just after the parachute opens—compare the skydiver’s apparent weight to the skydiver’s true weight. Provide a qualitative ranking (greater than, equal to, or less than true weight) and justify each comparison with reference to the forces acting on the skydiver.
(d) Describe how the skydiver’s sensation of weight changes as the descent progresses through the three phases listed in part (c), and connect your description to the concepts of normal force and weightlessness.