View Full Version : Hard physics
illGeno
Oct 15, 2007, 08:47 AM
A diver jumps vertically with a velocity of 4.0m/s from a platform and enters the water 1. seconds later. If she falls with an acceleration due to gravity of 9.8 m/s^2, what is her final velocity?
DoctorK
Oct 15, 2007, 11:26 AM
Vf= Final Velocity ?
Vo= Original Velocity 4 m/s
a= Acceleration 9,8 m/s^2
t= Time 1 s
Vf=Vo+a(t) 13,8 m/s
Capuchin
Oct 15, 2007, 11:31 AM
Vf= Final Velocity ?
Vo= Original Velocity 4 m/s
a= Acceleration 9,8 m/s^2
t= Time 1 s
Vf=Vo+a(t) 13,8 m/s
I believe the question requires v0 to be set as -4m/s, not +4m/s.
DoctorK
Oct 15, 2007, 11:53 AM
I believe the question requires v0 to be set as -4m/s, not +4m/s.
As the question states "A diver jumps vertically" I assumed the diver jumped DOWN in which case the original value is correct, and V0= +4.
If the diver jumps UPWARDS, then your appreciation is correct, and V0= -4.
asterisk_man
Oct 15, 2007, 12:21 PM
DoctorK, please demonstrate how to jump down. I'd love to see it. :)
Capuchin
Oct 15, 2007, 01:40 PM
DoctorK, please demonstrate how to jump down. I'd love to see it. :)
Had to spread the rep, but this is exactly the point I was trying to make (albeit subtly). Plugging numbers into an equation is fine and dandy, but not at the cost of common sense. :)