1. You lift a 450 newton bag of rice 1.2 metres and carry it a distance of 10 metres to the kitchen. How much work is done? and 2. Ramu carries groceries from a car to his house. Each bag of grocery weighs 40 N. He has 10 bags. He lifts each bag up 1 metre to carry it and then walks 10 m from his car to his house. In the first question we didn't mind the lifting distance and in the second question we didn't consider the distance travelled. Please give me explanation.
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In both questions the work done=0
1st case
Height was not considered because force was acting in the upward direction while the displacement was perpendicular to the force.
2nd case
The same is here, the force and displacement both are perpendicular to each other. So now
Work done = force * displacement *cos theta
Now, theta = 90
So, cos 90= 0
So, work done = 0
If the displacement and force are perpendicular to each other then no matter how heigh the object is or what distance it has travelled
1st case
Height was not considered because force was acting in the upward direction while the displacement was perpendicular to the force.
2nd case
The same is here, the force and displacement both are perpendicular to each other. So now
Work done = force * displacement *cos theta
Now, theta = 90
So, cos 90= 0
So, work done = 0
If the displacement and force are perpendicular to each other then no matter how heigh the object is or what distance it has travelled
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