The examples of work being done on an object are:
a. Pushing a grocery cart through the store
d. Lifting a bag of groceries
e. Carrying a box up a flight of stairs
h. Lifting a rock off the ground
These actions involve exerting a force on an object that results in displacement, which is the definition of work in physics.
The other options do not qualify as work being done on an object for the following reasons:
b. Carrying a bag of groceries to the car - While you are exerting a force, if you are carrying it straight up and down, the vertical component of the force doesn't cause displacement in the direction of the gravitational force (only the force perpendicular to gravity does).
c. Wind blowing against a tree - While there is force, the tree does not move, so work is not done.
f. Holding a 25 kg barbell over your head - No displacement occurs despite there being force applied.
g. Pushing on a car that will not move - No displacement occurs, so no work is done.
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