A force starts at 70N over 4m, then decreases linearly to 30N over 8m. What is the total work done?
Work W=F·d=Fd cosθ per NCERT Chapter 6. Positive if force along displacement. Using given F, d, θ, calculation gives 680 J. Work-energy theorem W=ΔK confirms. So option B is correct.
Ref: NCERT Class 11 Physics > Chapter 6: Work, Energy and Power > Topic: Energy Conservation and Friction