A Person in Free Fall Newton's 2nd Law

  • Thread starter dacabbo
  • Start date
  • #1
1
0
A Person in "Free Fall" Newton's 2nd Law

Homework Statement


An 80kg aviator is in free fall and acquires a velocity of 60 m/s and then opens his parachute.
After falling an additional 30m, his velocity has been reduced to 20 m/s. What is the average acceleration of the aviator while his fall is being checked? What is the average force being exerted by the parachute?


Homework Equations


Force = Mass * acceleration
Average acceleration = change in velocity/change in time


The Attempt at a Solution


Any help would be appreciated, Dont understand how to go about problem
 

Answers and Replies

  • #2
HallsofIvy
Science Advisor
Homework Helper
41,833
956


If a person has intial speed [itex]v_0[/itex] and constant acceleration [itex]a[/itex] has, after time t, speed [itex]at+ v_0[/itex] and will have gone distance [itex](a/2)t^2+ v_0t[/itex]. So we will fall "an additional 30m" when [itex](a/2)t^2+ 60t= 30[/itex]. Solve the quadratic equation [itex](a/2)t^2+ 60t- 30= 0[itex] for t. Of course, that will depend on a. Put that value of t into [itex]at+ 60= 20[/itex] and solve that equation for a.
 

Related Threads on A Person in Free Fall Newton's 2nd Law

  • Last Post
Replies
2
Views
2K
Replies
2
Views
5K
  • Last Post
Replies
4
Views
559
  • Last Post
Replies
8
Views
2K
  • Last Post
Replies
2
Views
1K
  • Last Post
Replies
8
Views
961
  • Last Post
Replies
17
Views
8K
  • Last Post
Replies
11
Views
2K
  • Last Post
Replies
15
Views
3K
  • Last Post
Replies
2
Views
1K
Top