Travelling in an elevator (not freefalling)

danimation3d

New member
Joined
Jun 5, 2013
Messages
1
Hi all,
I'm trying to solve a very trivial question my friends have...
If one was travelling upward in a regular elevator, and the elevator was to suddenly stop, would there be enough momentum for the occupant to hit their head on the ceiling?
We're assuming there is only one occupant, who is 70kg, and the elevator is travelling at a rate of 2 meters per second.
If someone could show me how to work this one out, it would be much appreciated :D

Thanks

Dan
 
First of all, the occupant has the kinetic energy of Ek=(1/2)*m*v2 with m=Mass in kg v= speed in m/s
If the elevator stops Ek converts to potential Energy Ep= m*g*h with g = 9,81 m/s2 and h = height.
Now set Ek= Ep​ and transform it to h = .... to figure out how high the occupant will get.
 
Another way:

When elevator suddenly stops, you are moving upwards with a speed of 2 m/s.

If throw ball up with a speed of 2 m/s, how high the ball would go? standard Galileo's equation:

v2 = u2 + 2as → 0 = 22 - 2*9.81*s → s = 2/9.81 = ~ 0.2 m.

In standard elevator, for a standard person there should be enough headroom > 20 cm.
 
Top