General Knowledge - Physics - Discussion

We need explanation please.

Work done in rolling is less than lifting due to a extra work has been done in lifting due to gravity means against the gravity but in rolling on a inclined plane we get a work done by gravity in downward direction along the gravity.

Work done in rolling case also include frictional coifficient of both the surface which reduce word done as compair to lifting.

Like pulling is easier than pushing. Concept of friction.

Work done in rolling is less than lifting due to gravity.

Let's consider the comments of both vivek & rajal here.

1) when the body is supposed to lift upwards the gravity acts on it in the opposite direction (downwards).

2) when its rolled on an inclined surface the acts frictional force. But the work done is more in lifting upwards this is because for our consideration let it be mass=1kg,then weight=9.8N(w=m*g)

Then you need a force greater than the weight.But when its to move inclined instead of vertical less force is needed.

Let us consider its inclined at an angle of 1o degree then the body exerts a vertical force of (9.8*sin10)N and horizontal force of (9.8*cos10)N .

Now compare the case 1 & case 2 this shows that a body can be moved in (horizontal & inclined) easily than vertically.

[Note :to get the horizontal & vertical components refer parallelogram law]

Thank you a lot for reading my comment.

Force of gravity acting on stone in vertical position is greater than that of fprce acting during slidding position.

When we lift the block,we have to work against the gravitational force Mg but to roll the block up on the inclined plane it requires less work as Mg gets resolved.

How is option B and D different?

The answer is C. Work is force times distance. In this case, the force is the mass times gravity. Rolling up the hill reduces the magnitude of the force but increases the distance by the same magnitude, thus making the work the same; the rate is just decreased.