Chapter 6, Problem 48A

After she jumps, a sky diver reaches terminal speed after 10 seconds. Does she gain more speed during the first second of fall or the ninth second of fall? Compared with the first second of fall, does she fall a greater or a lesser distance during the ninth second?

To determine

Speed during the first second of the fall and the ninth second of the fall.

Answer to Problem 48A

She gains more speed during the first second of the fall. She falls a greater distance during the ninth second.

Explanation of Solution

Introduction:

Acceleration of an object is defined as the change in velocity during given interval of time. So, as the skydiver jumps the speed will be gained more likely in the first second of the fall because it started from rest to motion. So, she gained more speed during the first second of the fall.

During the downward motion of the skydiver, her speed will be increasing and she will fall faster than before during the last second. Hence, speed increases in the last second of the fall. The speed is given by the distance covered in definite time interval. So, it can be concluded that due to increase in speed, the distance will be greater. Compared to the first second of the fall, she falls a greater distance during the ninth second.

Conclusion:

She gains more speed during the first second of the fall. She falls a greater distance during the ninth second.