An object thrown at a certain angle to the ground moves in a curved path and falls back to the ground. The initial and the final points of the path of the object lie on the same horizontal line. What is the work done by the force of gravity on the object?

The work done against gravity is given by,

W=  Force × displacement =mg × h 

where,

W=work done, m=the mass of the object, g=acceleration due to gravity, h=vertical displacement.

Vertical displacement will be zero because the initial and final positions of the object lie in the same horizontal line.

Hence, W= m × g × 0

So,       W=0 joule.

Therefore, the work done by the force of gravity on the object is 0 J (zero).