Question

15. A frictionless sliding hockey puck and a rolling hoop both start from rest at the same initial height on the same side of a valley (same valley for both objects). Both objects have the same mass M. The hoop rolls without slipping. Assume no air resistance. The objects descend into the valley and then up onto the hillside on the right. Consider the following two statements: 1. The hoop has a greater maximum speed than the disk at the bottom of the valley. II. The hoop achieves a greater maximum height than the disk on the right side of the valley. sliding puck rolling Ohoop A. В. C. D. I only П only Both I and II are true. Neither are true.

Answer 1

here,

for sliding Puck

At the bottom of valley

using conservation of mechanical energy

the initial potential energy is converted in linear kinetic energy

and

for rolling hoop

At the bottom of valley

using conservation of mechanical energy

the initial potential energy is converted in linear kinetic energy and rotational kinetic energy

so, the speed of hoop is lesser than the puck at the bottom

BUT

both have same total kinetic energy

and

using conservation of mechanical energy

therefore achieve the same maximum height

so, D) Neither statement are true