Solving the Mystery of the Pigeon-Seeking Fall: Acceleration Calculations

AI Thread Summary
The discussion focuses on calculating the acceleration experienced by a person who falls 44.6 meters and lands on a garbage can, crushing it by 0.422 meters. The initial calculations involve using gravitational acceleration and kinematic equations for free fall. Participants suggest applying conservation of energy principles, where gravitational potential energy is converted into work done on the can. There is a debate about whether the original size of the garbage can is necessary for calculating the work, with some arguing it is not needed since the depth of the crush is provided. The conversation emphasizes the importance of understanding energy conservation in solving the problem.
GuitarHero
Messages
2
Reaction score
0

Homework Statement


A very silly person, intent on catching pigeons on the roof of an apartment building, trips and falls a distance of 44.6 m. She lands on a metal garbage can, crushing it to a depth of 0.422 m and walks away without having been seriously hurt. What acceleration did she experience during the collision?


Homework Equations


(see solution attempt)
and
d=v1t+1/2at2


The Attempt at a Solution


This is what I have so far for the first part of the problem (her acceleration, velocity, and position when she is free falling for 44.6m):
a=-9.81
v=-9.81t
d=-4.905t2+44.6

But I'm not sure how to factor in the acceleration of her crushing the garbage can...

Any help would be awesome!
 
Physics news on Phys.org
Conservation of energy would be better for this problem

Her gravitational pe is converted into the work done in crushing the can to the depth of 0.422m
 
rock.freak667 said:
Conservation of energy would be better for this problem

Her gravitational pe is converted into the work done in crushing the can to the depth of 0.422m

But wouldn't I need to know the original size of the garbage can to calculate the work required to crush it?
 
GuitarHero said:
But wouldn't I need to know the original size of the garbage can to calculate the work required to crush it?

I don't think you would, the can is crushed to that depth d, so W=Fd.
 
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
Thread 'Variable mass system : water sprayed into a moving container'
Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
Back
Top