An elevator and its load have a total mass of 800 kg . The elevator is originally moving downwards at 10 m s- 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 m s- 2 )

Question

An elevator and its load have a total mass of 800 kg . The elevator is originally moving downwards at 10 m s- 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 m s- 2 ) (A) 8000N (B) 1600N (C) 9600N (D) 6400N

Tardigrade Admin · Accepted Answer

As the elevator is going down with decreasing speed, so acceleration is upward duration, Let it is

a

T - 800 g = 800 a,

T = 800 (g + a)

From

v^{2} = u^{2} - 2 a s

,

∴ a = 2 m s^{- 2}

∴ T = 800 (10 + 2)

,

∴ T = 9600

N

$8000 N$

$1600 N$

$9600 N$

$6400 N$

As the elevator is going down with decreasing speed, so acceleration is upward duration, Let it is $a$

$T - 800 g = 800 a,$
$T = 800 (g + a)$
From $v^{2} = u^{2} - 2 a s$ ,
$∴ a = 2 m s^{- 2}$
$∴ T = 800 (10 + 2)$ ,
$∴ T = 9600$ N

Q. An elevator and its load have a total mass of 800kg . The elevator is originally moving downwards at 10ms−1 , it slows down to stop with constant acceleration in a distance of 25m . Find the tension T in the supporting cable while the elevator is being brought to rest. (Take g=10ms−2 )

8000N

1600N

9600N

6400N

As the elevator is going down with decreasing speed, so acceleration is upward duration, Let it is a T−800g=800a, T=800(g+a) From v2=u2−2as , ∴a=2ms−2 ∴T=800(10+2) , ∴T=9600 N

$8000 N$

$1600 N$

$9600 N$

$6400 N$

As the elevator is going down with decreasing speed, so acceleration is upward duration, Let it is $a$

$T - 800 g = 800 a,$
$T = 800 (g + a)$
From $v^{2} = u^{2} - 2 a s$ ,
$∴ a = 2 m s^{- 2}$
$∴ T = 800 (10 + 2)$ ,
$∴ T = 9600$ N