Finding time and final velocity


by physfall
Tags: acceleration, final, time, velocity
physfall
physfall is offline
#1
Sep27-09, 04:34 PM
P: 1
1. The problem statement, all variables and given/known data
A photographer in a helicopter ascending vertically at a constant rate of 12.5 m/s accidentally drops a camera out the window when the helicopter is 60.0 m above the ground.
-How long will it take the camera to reach the ground? What will its speed be when it hits?
a= -9.8 m/s^2 displacement=60 m

2. Relevant equations
(final v)^2=(initial v)^2 + 2*a*deltax
deltax=1/2a(t^2)+(initial v*t)



3. The attempt at a solution
initial v=0
so time will equal 3.5 s, and final velocity will equal 33.67 m/s^2
however, these are incorrect
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CompuChip
CompuChip is offline
#2
Sep27-09, 04:45 PM
Sci Advisor
HW Helper
P: 4,301
The initial v is not 0, but the v of the helicopter and photographer. If you don't believe is, look up some movies of a ball shot from a moving car: when the car is moving at 50 km/h and the ball is shot backwards at 50 km/h, it drops straight down.


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