Can the work by kinetic friction on an object be positive? Zero?
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Answered by
120
Answer ⇒ Yes, work done by the kinetic friction on the object can be positive and also zero.
Explanation ⇒
Work done by the kinetic friction on an object is always the negative because the displacement is always opposite to the the frictional force. Although in some cases work done by the kinetic friction can be both positive and zero.
Let us take the Examples of the Positive work and the Zero work done by the Kinetic Friction.
From the Positive Work,
Assume that the one object (say A) is kept over other and lower object(say B) starts to move with certain acceleration in such a way that object A slides over the object B.
In such an case, the Kinetic friction on the object A acts along the direction of motion of Object B.
Although, the object A will slides, but it will moves in the direction of the object B with less velocity than the object A.
Hence, work done by kinetic fiction in this example is positive.
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Example for the Zero work,
Assume that one Object is moving on the land. Kinetic friction in this case will be acting between the Object and the land.
Kinetic friction on the object will be acting back and on the land, it will be acting forwards. Since, there is no movement along this forward kinetic friction force, Hence, work done will be zero.
Thus, Work done by the Kinetic Friction on an Object can both the Positive and Zero. Sometimes It can be negative also.
Hope it helps.
Explanation ⇒
Work done by the kinetic friction on an object is always the negative because the displacement is always opposite to the the frictional force. Although in some cases work done by the kinetic friction can be both positive and zero.
Let us take the Examples of the Positive work and the Zero work done by the Kinetic Friction.
From the Positive Work,
Assume that the one object (say A) is kept over other and lower object(say B) starts to move with certain acceleration in such a way that object A slides over the object B.
In such an case, the Kinetic friction on the object A acts along the direction of motion of Object B.
Although, the object A will slides, but it will moves in the direction of the object B with less velocity than the object A.
Hence, work done by kinetic fiction in this example is positive.
___________________________
Example for the Zero work,
Assume that one Object is moving on the land. Kinetic friction in this case will be acting between the Object and the land.
Kinetic friction on the object will be acting back and on the land, it will be acting forwards. Since, there is no movement along this forward kinetic friction force, Hence, work done will be zero.
Thus, Work done by the Kinetic Friction on an Object can both the Positive and Zero. Sometimes It can be negative also.
Hope it helps.
Answered by
30
HEY!!
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⚫Yes. Let us consider a block A which is resting on another block B.
⚫Block B is resting on a smooth horizontal surface.
⚫Let the coefficient of friction between the blocks be μ.
⚫When a force F is applied on block B in the forward direction as shown in the above figure, block A moves with block B in the direction of the applied force.
⚫The frictional force on block A and the displacement will be in the forward direction.
⚫Therefore, work done by the frictional force is positive.
⚫If we consider the reference frame of block B, then displacement of block A will be zero.
⚫⚫Therefore, work done by the frictional force is zero.
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⚫Yes. Let us consider a block A which is resting on another block B.
⚫Block B is resting on a smooth horizontal surface.
⚫Let the coefficient of friction between the blocks be μ.
⚫When a force F is applied on block B in the forward direction as shown in the above figure, block A moves with block B in the direction of the applied force.
⚫The frictional force on block A and the displacement will be in the forward direction.
⚫Therefore, work done by the frictional force is positive.
⚫If we consider the reference frame of block B, then displacement of block A will be zero.
⚫⚫Therefore, work done by the frictional force is zero.
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