1. Tardigrade
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  3. Physics
  4. A lift ascends with constant acceleration a=1 m s- 2 , then with constant velocity and finally, it stops under constant retardation a=1 m s- 2 . If total distance ascended by the lift is 7 m , in a total time of the journey is 8 s . Find the time (in second) for which lift moves with constant velocity.

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Q. A lift ascends with constant acceleration $a=1 \, m \, s^{- 2}$ , then with constant velocity and finally, it stops under constant retardation $a=1 \, m \, s^{- 2}$ . If total distance ascended by the lift is $7 \, m$ , in a total time of the journey is $8 \, s$ . Find the time (in second) for which lift moves with constant velocity.

NTA AbhyasNTA Abhyas 2020Motion in a Straight Line

Solution:

$a=\frac{v}{t_{1}}$

Solution
$t_{1}=\frac{v}{a}$ ...(i)
$t_{0}=8-2t_{1}$ ...(ii)
$s_{0}=7-2s_{1}$ ...(iii)
Solving equation (i), (ii) and (iii), we get
$t_{0}=6s$