Chasing a free-falling person

  • Thread starter Ritchie
  • Start date
In summary, the hero needs to cover 1000 meters in a total of 23.81 seconds, and she has 1.9 seconds to accelerate before catching the person. The superhero's acceleration rate is 3.02 m/s2.
  • #1
Ritchie

Homework Statement


A hovering superhero notes a person fall past at a terminal velocity of 140 km/h. 1.9
seconds later, she begins to accelerate downwards and catches the person 1000 m
below. What was her rate of acceleration?

Homework Equations


d = v x t
d = vot + at2

The Attempt at a Solution


First I convert km/h to m/s for the persons velocity
140 / 3.6 = 38.88 m/s

1.9 seconds is essentially the superhero's reaction time so I find out how far the person goes in 1.9 seconds
38.88 x 1.9 = 73.88 m - but I have no idea what to do with this number

For the person to fall 1000 meters it would take
1000 / 38.88 = 25.71s

Now I isolate for a in the formula d = vot + at2
a = 2d/t2
a = 2000/661.22
a = 3.02 m/s2However according to the answers this answer is wrong. Can anybody help me and tell me what I'm doing wrong? I know I'm supposed to do something with that 73.88 m number but I don't know what. Can someone explain to me and tell me what it is used for?

 
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  • #2
Welcome!
The hero needs to cover 1000 m in how much time?
 
  • #3
TSny said:
Welcome!
The hero needs to cover 1000 m in how much time?

It took 1.9 seconds for the 73.88 meters so for the rest = 1000 - 73.88 = 926.12 meters
926.12 / 38.88 = 23.81 seconds + 1.9 seconds which still gives me the same amount of time?
 
  • #4
Suppose for the moment that the hero were to start her descent at the same instant that the person passes her. How much time does she have to catch the person at 1000 m below?
 
  • #5
This is probably easier if you look at absolute time values.

At t=0 s the person passes the superhero.
At t=1.9 s the superhero starts accelerating
At t=? the falling person is 1000 m below the starting point.

=> the superhero accelerates for ?? seconds
 

What is the concept of chasing a free-falling person?

Chasing a free-falling person refers to the act of pursuing someone who is falling without any means of support or control in order to prevent them from hitting the ground and potentially getting injured or killed.

What are the potential dangers of chasing a free-falling person?

The main danger of chasing a free-falling person is the risk of injury to both the person falling and the person chasing them. This can be caused by collisions, falls, or other accidents during the chase.

What are some safety precautions that should be taken when chasing a free-falling person?

It is important to assess the situation carefully and make sure you have the necessary skills and equipment before attempting to chase a free-falling person. It is also important to communicate clearly and coordinate with any other people who may be involved in the rescue.

What are the physical capabilities required for chasing a free-falling person?

Chasing a free-falling person can be physically demanding and requires a certain level of fitness, agility, and strength. It is important to be able to run, climb, and maneuver quickly and effectively in order to catch up with the falling person.

What are some alternative methods for rescuing a free-falling person?

If chasing a free-falling person is not possible or safe, there are alternative methods for rescuing them such as using a safety net, deploying a parachute, or using a harness system to lower them safely to the ground.

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