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In which of the following cases is the work done positive?
  • a)
    Work done by friction on a body sliding down an inclined plane
  • b)
    Work done by gravitational force while a man in lifts a bucket out of a well by means of a rope tied to the bucket
  • c)
    Work done by the resistive force of air on a vibrating pendulum in bringing it to rest.
  • d)
    Work done by an applied force on a body moving on a rough horizontal plane with uniform velocity
Correct answer is option 'D'. Can you explain this answer?
Verified Answer
In which of the following cases is the work done positive?a)Work done ...
Explanation:When a body is moving on a rough horizontal surface then their will be 2 forces acting on the body   1. Applied force ( in the direction of motion) 2. friction ( opposite to direction of motion)As applied force is in same direction as displacement so work done will be positive.
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Most Upvoted Answer
In which of the following cases is the work done positive?a)Work done ...
Work done is defined as the product of the force applied on an object and the displacement of the object in the direction of the force. If the force and displacement are in the same direction, the work done is positive. If they are in opposite directions, the work done is negative.

a) Work done by friction on a body sliding down an inclined plane:
In this case, the frictional force opposes the motion of the body, and it acts in the opposite direction to the displacement. Hence, the work done by friction is negative.

b) Work done by gravitational force while a man lifts a bucket out of a well:
When the man lifts the bucket, the force exerted by the man is in the upward direction, and the displacement of the bucket is also in the upward direction. The gravitational force, on the other hand, acts in the downward direction. Since the force and displacement are in opposite directions, the work done by the gravitational force is negative.

c) Work done by the resistive force of air on a vibrating pendulum in bringing it to rest:
As the pendulum is brought to rest, the resistive force of air acts in the direction opposite to the displacement. Therefore, the work done by the resistive force of air is negative.

d) Work done by an applied force on a body moving on a rough horizontal plane with uniform velocity:
In this case, the applied force and the displacement are in the same direction. The work done by the applied force is given by the formula W = F * d * cosθ, where θ is the angle between the force and displacement vectors. Since the force and displacement are parallel, the angle θ is 0°, and the cosine of 0° is 1. Therefore, the work done is positive.

Hence, the correct answer is option D, where the work done by an applied force on a body moving on a rough horizontal plane with uniform velocity is positive.
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In which of the following cases is the work done positive?a)Work done by friction on a body sliding down an inclined planeb)Work done by gravitational force while a man in lifts a bucket out of a well by means of a rope tied to the bucketc)Work done by the resistive force of air on a vibrating pendulum in bringing it to rest.d)Work done by an applied force on a body moving on a rough horizontal plane with uniform velocityCorrect answer is option 'D'. Can you explain this answer?
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In which of the following cases is the work done positive?a)Work done by friction on a body sliding down an inclined planeb)Work done by gravitational force while a man in lifts a bucket out of a well by means of a rope tied to the bucketc)Work done by the resistive force of air on a vibrating pendulum in bringing it to rest.d)Work done by an applied force on a body moving on a rough horizontal plane with uniform velocityCorrect answer is option 'D'. Can you explain this answer? for Class 11 2024 is part of Class 11 preparation. The Question and answers have been prepared according to the Class 11 exam syllabus. Information about In which of the following cases is the work done positive?a)Work done by friction on a body sliding down an inclined planeb)Work done by gravitational force while a man in lifts a bucket out of a well by means of a rope tied to the bucketc)Work done by the resistive force of air on a vibrating pendulum in bringing it to rest.d)Work done by an applied force on a body moving on a rough horizontal plane with uniform velocityCorrect answer is option 'D'. Can you explain this answer? covers all topics & solutions for Class 11 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for In which of the following cases is the work done positive?a)Work done by friction on a body sliding down an inclined planeb)Work done by gravitational force while a man in lifts a bucket out of a well by means of a rope tied to the bucketc)Work done by the resistive force of air on a vibrating pendulum in bringing it to rest.d)Work done by an applied force on a body moving on a rough horizontal plane with uniform velocityCorrect answer is option 'D'. Can you explain this answer?.
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