LIVE Course for free

Rated by 1 million+ students
Get app now
0 votes
39 views
in Physics by (30.0k points)
closed by
The work done by the force of friction on a body sliding on a rough horizontal surface will be-
1. Positive
2. Negative
3. Zero
4. Constant

1 Answer

0 votes
by (54.0k points)
selected by
 
Best answer
Correct Answer - Option 2 : Negative

The correct answer is option 2) i.e. Negative.

CONCEPT:

  • Work done by a force: Work is said to be done by a force on a body when there is a displacement of the body due to that force.

The magnitude of work done is given as:

W = F.S.Cosθ

where, W = Magnitude of work done by the force(F) in joule, F = Magnitude of force, in newton, SCosθ  = Component of the Displacement in the direction of the force, in meter

  • Positive and negative work: When the force and the displacement are in the same direction, work done is positive.
    • When the force and displacement are in opposite direction, work done is negative.
  • Zero work done: Work done is zero if force and displacement are perpendicular to each other or if the displacement of the body is zero.

EXPLANATION:

  • When a body is sliding on a rough horizontal surface, the force of friction acts in the direction opposite to the direction of motion.
  • Hence, force and displacement are in opposite direction.
  • Therefore, work done by the force of friction on a body sliding on a rough surface is negative.

  • If the force and displacement are in the same direction, the work done is positive.
  • If force and displacement are perpendicular to each other, the work done is zero.
  • A constant work done happens when neither the magnitude nor the direction of either force or displacement is changing.

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.

Categories

...