OnlineCBT
Physics · PYQ NEET UG 2017
हिन्दीPreeti reached the metro station and found that the escalator was not working. She walked up the stationary escalator in time \( t_1 \). On other days, if she remains stationary on the moving escalator, then the escalator takes her up in time \( t_2 \). The time taken by her to walk up on the moving escalator will be:
View Answer & Solution
Correct answer · Option C
\( \frac{t_1 t_2}{t_2 + t_1} \)
Explanation
Let distance be \( d \). Person's speed \( v_p = \frac{d}{t_1} \), escalator's speed \( v_e = \frac{d}{t_2} \). Effective speed when both move is \( v = v_p + v_e = d(\frac{1}{t_1} + \frac{1}{t_2}) \). Time \( t = \frac{d}{v} = \frac{t_1 t_2}{t_1 + t_2} \).
