A disk and a sphere of same radius but different masses roll on two inclined planes of the same altitude and length. Which one of the two objects gets to the bottom of the plane first ?

A disk and a sphere of same radius but different masses roll on two in

1.	A disk and a sphere of same radius but different masses roll on two inclined planes of the same altitude and length. Which one of the two objects gets to the bottom of the plane first ?
Answer» <html><body><p> Sphere</p><br/><br/><p>The sphere will reach the <a href="https://interviewquestions.tuteehub.com/tag/bottom-401202" style="font-weight:bold;" target="_blank" title="Click to know more about BOTTOM">BOTTOM</a> faster than the <a href="https://interviewquestions.tuteehub.com/tag/disk-955870" style="font-weight:bold;" target="_blank" title="Click to know more about DISK">DISK</a>. It is because the disk has a higher rotational inertia than the solid:<br/>I= mr²<br/>I is the rotational inertia where m is the <a href="https://interviewquestions.tuteehub.com/tag/mass-1088425" style="font-weight:bold;" target="_blank" title="Click to know more about MASS">MASS</a> and r is the square of distance from the axis of rotation. in the case of disk I is greater due to r and more the I, more is the rotational K.E. Then for conservation of energy Translational K.E will be less.<br/>mgh= K.E (T) + K.E (R)<br/>so in case of sphere translational K.E will be more, meaning more <a href="https://interviewquestions.tuteehub.com/tag/final-461168" style="font-weight:bold;" target="_blank" title="Click to know more about FINAL">FINAL</a> velocity and it will reach the bottom faster.</p></body></html>