Question

A solid sphere, disc and solid cylinder all of the same mass and made of same material are allowed to roll down (from rest) on inclined plane then
1. Disc will reach the bottom first
2. Solid sphere will reach the bottom first
3. Solid cylinder will reach the bottom first
4. All of them will reach the bottom at the same time

Answer 1

Correct Answer - Option 2 : Solid sphere will reach the bottom first

The correct answer is Solid sphere will reach the bottom first.

• By comparing the moment of Inertia of the above three objects, we found that 

• I_c  = ½ MR²

  I_S =  2/5 MR²

  I_D  =  ½ MR²

• The moment of inertia of the Solid Sphere is smaller than the other two.

• It means its angular acceleration will be highest and hence, It will roll faster and reaches the bottom first.