Q. An elevator and its load have a total mass of 800 kg. The elevator is originally moving downwards at $10\ ms^{- 1}$, it slows down to stop with constant acceleration in a distance of 25 m. Find the tension $T$ in the supporting cable while the elevator is being brought to rest. (Take $g = 10\ ms^{- 2}\ $)
A) 8000 N
B) 1600 N
C) 9600 N
D) 6400 N
Explanation
(c) As the elevator is going down with decreasing speed, so acceleration is upward duration, Let it is $a$
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$T - 800g = 800a,$
$T = 800(g + a)$
From $v^{2} = u^{2} - 2as$,
$\therefore\ a = 2ms^{- 2}$
$\therefore\ T = 800(10 + 2)$,
$\therefore\ T = 9600$ N
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.