Work, Power and EnergyHard
Question
A man of mass m standing at the bottom of the staircase of height L climbs it and stands at its top
Options
A.Work done by all forces on man is equal to the rise in potential energy (mgL)
B.Work done by all forces on man is zero.
C.Work done by the gravitational force on man is mgL.
D.The reaction force from a step does not do work because the point of application of the force does not move while the force exists.
Solution
Work done by all forces include work done by man himself.
Applying work energy theorem; Wall = ᐃKE
Since man finally comes to rest ⇒Wall = 0
Work is done by a force only when point of application of force moves in the direction of force applied.
Applying work energy theorem; Wall = ᐃKE
Since man finally comes to rest ⇒Wall = 0
Work is done by a force only when point of application of force moves in the direction of force applied.
Create a free account to view solution
View Solution FreeMore Work, Power and Energy Questions
A pendulum bob of mass m is suspended at rest. A constant horizontal force F = mg /2 starts acting on it. The maximum an...A metal ball does not rebound when struck on a wall, whereas a rubber ball of same mass when thrown with the same veloci...A frictionless track ABCDE ends in a circular loop of radius R. A body slides down the track from point A which is at a ...Consider a roller coaster with a circular loop. A roller coaster car starts from the top of a hill which is 5 M higher t...Two elastic bodies P and Q having equal masses are moving along the same line with velocities of 16 m/s and 10 m/s respe...