General Knowledge - Physics - Discussion

Because in lifting a ball work done is against gravity and so large effort is to be applied than to roll it.

Work done is less if the object rolling and greater work is done if object lifting.

Since in a simple machine effort * effort arm = load * load arm.

In this case it is effort * hypotenuse of the rt angled triangle = load * perpendicular.
But perpendicular<hypotenuse.
Therefore effort<load.

Since, the coefficient of rolling friction is less than the coefficient of sliding friction, the work done in rolling becomes less than lifting.

It is easy to roll down because the work is done when we throw it in vertical direction.

Whether you lift the stone or roll it up the slope ,stone gains potential energy equal to mgh .The stone gained this energy and by same amount you lost it ! Frictional force at the time of rolling up makes you to loose a little more of energy. You would have lost energy mgh when you lift it and mgh+ when you roll it up . Is it not better to lift then to roll it? Catch is here. There is mechanical advantage when you roll. Lever principle can be applied . Let the slope be 1/10. Rolling distance is 10 units whereas the lifting distance remains 1 unit . The effort is 1/10 now. You have a convenient comfort level ! In an ideal condition work done is same in both the cases. Rate of energy spending is less because you travel more distance. You spent less effort 1/10 and travelled 10 times more distance. Answer C is correct.

Work done in lifting is not more or less we feel it more due to the gravitational force acting on that object in same way we have to push it so no force required against gravity.

Here we have to consider the concept of inclined plane no doubt the amount of work done is same either we do it by rolling or pulling but one of the benefit is that gravitation force will be neglected.

More the slope less will be the effort.

D is the right answer that is true.

Stephen is not right bcoz work = force*displacement(not distance).So,option D is right.