A person weighs 150 pounds. He is standing on a scale inside an elevator. If the elevator is free-falling downward (perhaps the cable broke), what is the reading of the scale?
150 pounds
about 25 pounds
0 pounds
not enough info
7 answers
Total force on person = m g = m a in free fall. No external force on person from scale
so 150?
No !!! ZERO no force on scale - in free fall, accelerating downward at 9.81 m/s^2
Like - "weightless" :)
Backup link :)
http://www.jiskha.com/display.cgi?id=1282164495
http://www.jiskha.com/display.cgi?id=1282164495
Oh so 0 pounds :)
Yes 0
free falling
weightless :)
free falling
weightless :)