The rolling disk has both translational kinetic energy and rotational kinetic energy. The translational kinetic energy will grow more slowly compared the box that converts potential energy to translational kinetic energy only.
An Unfair Race This applet shows the results of releasing a frictionless block and a rolling disk with equal masses from the top of identical inclined planes.
Which of the following is the best explanation of the results shown in the applet? Which of the following is the best explanation of the results shown in the applet?
a) The disk loses energy to friction as it rolls, but the box is frictionless and so it speeds up more quickly and gets to the bottom first.
b) The potential energy of the disk is converted into translational and rotational kinetic energy, so the translational speed grows more slowly than that of the box, which has no rotational energy.
c) The net forces on the two objects are equal, but the force on the disk gets partially used up in creating the torque necessary to make it roll.
d) The net forces on the two objects are equal, but the force on the disk is not directed parallel to the ramp, and so does not create as great an acceleration down the ramp.
Frequently Asked Questions
What scientific concept do you need to know in order to solve this problem?
Our tutors have indicated that to solve this problem you will need to apply the Conservation of Energy with Rotation concept. You can view video lessons to learn Conservation of Energy with Rotation. Or if you need more Conservation of Energy with Rotation practice, you can also practice Conservation of Energy with Rotation practice problems.