Browse by Stream
QnA
Home
QnA
Go To Your Study Dashboard

Get Answers to all your Questions

header-bg qa
  • Home
  • Medical
  • Help me answer: 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 remains stationary on the moving escalator, then the escalator takes her up in tim

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 remains stationary on the moving escalator, then the escalator takes her up in time t2. The time taken by her to walk up on the moving escalator will be:

  • Option 1)

    \frac{t_{1}t_{2}}{t_{2}-t_{1}}

  • Option 2)

    \frac{t_{1}t_{2}}{t_{2}+t_{1}}

  • Option 3)

    t_{1}-t_{2}

  • Option 4)

    \frac{t_{1}+t_{2}}{2}

 

Answers (1)

best_answer

As we learnt in

Case of Relative velocity -

When A & B are moving along with straight line in opposite direction.

vec{V}_{A}= Velocity of object A.

vec{V}_{B}= Velocity of object B.

Relative velocity of A with respect to B is.

vec{V}_{AB}=vec{V}_{A}-(-vec{V}_{B})

-vec{V}_{B}  is because of opposite direction.

vec{V}_{AB}=vec{V}_{A}+(vec{V}_{B})

 

 

- wherein

E.g A body moves in east with speed of 20m-1, And body in west with velocity of 5ms-1.

Find velocity of A with respect to B.

vec{V}_{AB}=vec{V}_{A}+(vec{V}_{B})

= (20+5 ) ms-1

= 25 ms-1

 

 

 

 V_{1}=  Velocity of Preeti

 

V_{2}\rightarrow Velocity of escalator

l\rightarrow distance

t= \frac{l}{v_{1}+v_{2}}=\frac{l}{\frac{l}{t_{1}}+\frac{l}{t_{2}}}

=\frac{t_{1}t_{2}}{t_{1}+t_{2}}

Correct option is 2.


Option 1)

\frac{t_{1}t_{2}}{t_{2}-t_{1}}

Incorrect

Option 2)

\frac{t_{1}t_{2}}{t_{2}+t_{1}}

Correct

Option 3)

t_{1}-t_{2}

Incorrect

Option 4)

\frac{t_{1}+t_{2}}{2}

Incorrect

Posted by

prateek

View full answer

NEET 2024 Most scoring concepts

    Just Study 32% of the NEET syllabus and Score up to 100% marks

Similar Questions

Trending Articles/News

anam-khan

NEET UG 2024 exam city slip out at neet.ntaonline.in; over 25 lakh candidates to appear
anam-khan

NEET UG city intimation slip likely today at exams.nta.ac.in/NEET; barred item at exam centre
anam-khan

NEET UG 2024 exam city slip soon; admit card updates

Latest Question