Question

Why is it easier to pull than to push a lawn roller?

Answer 1

The force applied to move a body depends upon the effective force applied on it including its weight. As effective weight in the case of pulling is less than in the pushing, less force is required in pulling. Hence, it is easier to pull than to push.
In case of pulling, effective weight of lawn mover = mg-f sin θ
pushing, effective weight = mg+ f sin θ

In pushing frictional force is greater than that of in case of pulling. When you push you to add some normal of mg, so friction also increases but in case of pulling at the time you are pulling you decrease the normal so friction reduced and & it becomes easier.