Question

5. A woman pushes a box on railway platform which has rough surface. She applies a force of 20 N over a distance of 5 m thereafter gets tired and applied force which reduces linearly to 10 N with distance. The total distance which box has been moved is 10 m. Work done during second displacement is [NCERT Pg. 119] (1) 175 J (2) 19.5 J (3) 75J (4) 14.65 J​

Answer 1

Answer:

Work done by the force applied by woman

W1= area of rectangular OABD

+ area of trapezium BCED

=OA×OD+(BD+CE2)DE

=100×10+(100+502)10=1000+750

=1750J

Work done by frictional force

W2=− area of rectangular OGHE

=−OG×OE=−50×20=−1000J