A man lifts a 10 kg sack of rice from a ground to above his head using his both hands. The sack of

rice does not experience a change in kinetic energy between the two positions. Which of the
following statement is correct?
A The work done on rice sack by gravity is less than the work done on rice sack by man.
B The work done on rice sack by gravity is more than the work done on rice sack by man
C The work done on rice sack by gravity is equal to the work done on rice sack by man.
D There is no work done on the rice sack

can u please clarifie this doubt for me

the work done by gravity = - m g h (F down, motion direction x up)

the work done by the man = + m g h (F up, motion direction x up)

D There is no work done on the rice sack.

In order to determine the correct statement, we need to understand the concept of work done. Work is defined as the product of force and displacement, and it represents the transfer of energy.

Let's break down the situation described in the question:

The man lifts a 10 kg sack of rice from the ground to above his head using both hands. The fact that the sack of rice does not experience a change in kinetic energy means that its final velocity is the same as its initial velocity. This implies that the work done on the rice sack by gravity is equal to the work done on the rice sack by the man.

Gravity exerts a force on the rice sack, pulling it downwards. When the man lifts the sack against this force, he exerts an equal and opposite force to keep the sack from falling. The work done on the rice sack by gravity is given by the equation W = mgh, where m is the mass of the sack (10 kg), g is the acceleration due to gravity, and h is the height through which the sack is lifted.

Similarly, the work done on the rice sack by the man is also given by the equation W = mgh, where m is the mass of the sack, g is the acceleration due to gravity, and h is the height through which the sack is lifted.

Therefore, the correct statement is option C: The work done on the rice sack by gravity is equal to the work done on the rice sack by the man.