Q. A body of mass 1 kg is thrown upwards with a velocity 20 m/s. It momentarily comes to rest after attaining a height of 18 m. How much energy is lost due to air friction? (g = 10 m/s²)
A) 30 J
B) 40 J
C) 10 J
D) 20 J
Explanation
[Solution from source] Initial KE = ½ × 1 × 20² = 200 J. PE at 18 m = 1 × 10 × 18 = 180 J. Energy lost to air friction = 200 − 180 = 20 J. Answer (4).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.