KCET2020PhysicsMotion in One Dimension
At a metro station, a girl walks up a stationary escalator in 20 ~s . If she remains stationary on the escalator, then the escalator take her up in 30 ~s . The time taken by her to walk up on the moving escalator will be
Options
- A25 ~s
- B60 ~s
- C12 ~s
- D10 ~s
Correct answer
C. 12 ~s
Step-by-step solution
Let h be the height of platform, then speed of walking (v_ g )= h 20 Speed of escalator (v_ e )= h 30 Time taken by girl when she walk up on the moving escalator is t= h v_ g +v_ e = h h 20 + h 30 = 20 30 (30+20) =12 ~s