- #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?