JEE Main 2024 Physics question
A solid circular disc of mass 50 kg rolls along a horizontal floor so that its center of mass has speed of 0.4 m/s. The absolute value of work done on the disc to stop it is J.
Answer: 6
Solution
The total kinetic energy of a rolling disc is ½(mR²/2)(v²/R²) + ½mv² = (3/4)mv². So W = (3/4)(50)(0.4)² = 6 J.