Sample 1Medium
A force-displacement graph has x (m) on the horizontal axis and F (N) on the vertical axis. F is constant at 10 N from x = 0 to x = 2 m and then decreases in a straight line to 0 N at x = 4 m. How much work does the force do from x = 0 to x = 4 m?
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The answer is B.
Work is the area under the F-x graph: rectangle 10 × 2 = 20 J plus triangle 1/2 × 2 × 10 = 10 J, total 30 J.
- A.
20 J counts only the rectangle and leaves out the triangle from 2 m to 4 m.
- C.
40 J treats the force as 10 N over the whole 4 m.
- D.
10 J counts only the triangle.
NCERT: Class 11 Physics, Chapter 5