0

Guest

Courses New
  • Forum
  • AIPMT
  • Preeti reached the metro station and found...

Preeti 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 remaines stationary on moving esclalator, then the escalator takes her up in time t 2 . The time taken by her to walk up on the moving escalator will be 1) t 1 + t 2 / 2 2) t 1 t 2 /t 2 - t 1 3) t 1 t 2 / t 2 + t 1 4) t 2 - t 1 Now I have solved the question and I am getting answer (2) but answer is (3) as shown is attachment . Dont relative velocities of two body moving in same direction is found out by subtraction.? Please explain.

Preeti reached the metro station and found that the escalator was not working. She walked up the stationary escalator in time t1. On other days, if she remaines stationary on moving esclalator, then the escalator takes her up in time t2. The time taken by her to walk up on the moving escalator will be
 
1) t1 + t2 / 2
2) t1t2/t2 - t1
3) t1t2 / t2 + t1
4) t2 - t1
 
Now I have solved the question and I am getting answer (2) but answer is (3) as shown is attachment . Dont relative velocities of two body moving in same direction is found out by subtraction.?
 
Please explain.

Question Image
Grade:12th pass

1 Answers

Eshan
askIITians Faculty 2095 Points
5 years ago
Dear student,

\dfrac{d}{t_1}is not the velocity of Preeti(wrt ground), but of Preeti wrt escalator =v_{PE}. This is because it is her velocity when escalator is stationary.

Hence speed of Preeti on moving escalator==v_{PE}+v_E=\dfrac{d}{t_1}+\dfrac{d}{t_2}

Hope it helps. Regards.

Think You Can Provide A Better Answer ?

Other Related Questions on AIPMT

View all Questions »

ASK QUESTION

Get your questions answered by the expert for free

Answer and earn gift vouchers

Win Gift vouchers upto Rs 500/-

View courses by askIITians

Design classes One-on-One in your own way with Top IITians/Medical Professionals

Click Here Know More

Complete Self Study Package designed by Industry Leading Experts

Click Here Know More

Live 1-1 coding classes to unleash the Creator in your Child

Click Here Know More

a Complete All-in-One Study package Fully Loaded inside a Tablet!

Click Here Know More