A boy carrying a box on his head walking on an inclined road from one place to another is doing no work. this statement is
a.corret
b.incorrect
c.paritially correct
d.none of these
This statement is incorrect.
If the boy carries load on his head, in order to support it against the gravitational force acting on the load, the boy must exert a vertically upward force on the load. Now if the boy moves on a level ground, the angle between force and displacement becomes 90 degrees and the work done is zero. But as the boy is moving on an inclined road, the angle between force applied on the load and the displacement is not 90 degrees. Hence, the work done is also not zero.
If the boy carries load on his head, in order to support it against the gravitational force acting on the load, the boy must exert a vertically upward force on the load. Now if the boy moves on a level ground, the angle between force and displacement becomes 90 degrees and the work done is zero. But as the boy is moving on an inclined road, the angle between force applied on the load and the displacement is not 90 degrees. Hence, the work done is also not zero.