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What work should a man do to walk up a s...

What work should a man do to walk up a subway escalator moving down with speed `v` ? The height of the escalator is `h`, and the man walks up the escalator at a speed u.

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The correct Answer is:
`mgh(1+(v)/(u+v))`
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NN GHOSH-FRICTION, WORK POWER AND ENERGY-Exercises (B)
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  2. The total mass of an elevator with a 80 kg man in it is 1000 kg. This ...

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  3. Two masses 1.65 kg and 3.30 kg are joined together by a massles rod pa...

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  4. A body of mass m was slowly hauled up the hill as shown in the fig. by...

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  5. Following are three equations of motion S=ut+(1)/(2)at^(2) v(s)=s...

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  6. An escalator joins one floor with another 10 m above. The escalator is...

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  7. A ball of mass m is projected horizontally with velocity v into the ba...

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  8. A block of mass 2kg slides on a frictionless table with with a speed o...

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  9. An ideal massless spring is compressed by 1 m by a force of 100 N. The...

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  10. Masses M(1),M(2) and M(3) are connected by string of negligible mass w...

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  11. The handles of a table-drawer are equidistant from the sides of the dr...

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  12. A fixed pulley carries a weightless thread with masses m(2) and m(1) a...

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  13. A block of mass m is placed on the rough incline of a wedge of mass M ...

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  14. A car starts moving from rest along the circumference of a horizontal ...

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  15. A block of mass m=37.5 kg is placed on a table of mass M = 12.25 kg wh...

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  16. Water from the bottom of a dam of depth h comes out through a narrow p...

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  17. A 60 kg man leaps vertically from a crouching position when his centre...

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  18. What work should a man do to walk up a subway escalator moving down wi...

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  19. An object of mass m slides down a hill of height h and of arbitrary sh...

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  20. A skater standing on a perfectly floor holds on the nearby railing and...

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