question_answer

The relationship between the force F and position x of a body is as shown in figure. The work done in displacing the body from x = 1 m to x = 5 m will be       [KCET 2005]

A)             30 J

B)             15 J

C)             25 J

D)             20 J

Correct Answer: B

Solution :

                Work done = area under F-x graph                         = area of rectangle ABCD + area of rectangle LCEF                         + area of rectangle GFIH + area of triangle IJK \[=(2-1)\times (10-0)+(3-2)(5-0)+(4-3)(-5-0)\]                                     \[+\frac{1}{2}(5-4)(10-0)\]\[=15\,\,J\]