A 1g drop falls from 800m and hits the ground at 30m/s. What is the work done by air resistance? (Take g\=10m/s2)
Work W=F·d=Fd cosθ per NCERT Chapter 6. Positive if force along displacement. Using given F, d, θ, calculation gives -7.55 J. Work-energy theorem W=ΔK confirms. So option B is correct.
Ref: NCERT Class 11 Physics > Chapter 6: Work, Energy and Power > Topic: Collisions and Power
