Force, Acceleration, Gravity, and Weight

when an elevator moves upward with a constant speed , why doesnot apparent weight increases as for an elevator to maintain a constant speed under the influence of gravity , a continous force has to be applied which will cause some acceleration in the lift , hence the weight should increase ?
- SUMIT JOSHI (age 16)
DELHI , INDIA

The force on the elevator required to keep it at constant upward speed is exactly the same as the force required to keep it at zero speed. The weights in the elevator won't change. The force "which will cause some acceleration in the lift" is larger than that. If there is upward acceleration, then the weights measured in the elevator will increase. By definition, however, that's not the case of "constant speed".

Mike W.

(published on 08/21/2013)