Classical Mechanics
# Rotational Kinetic Energy

A solid ball rolls on a slope from rest starting from a height of \(H=7.0\text{ m}\) and then rolls on a horizontal region, as shown in the above figure. The horizontal distance of the slope and the distance of the horizontal region are both equal to \(L=6 \text{ m},\) and the height of the horizontal region is \(h=3.0\text{ m}.\) Approximately how far horizontally from point \(P\) does the ball hit the floor?

The rotational inertia of a solid sphere about any diameter is \(I=\frac{2}{5}MR^2,\) where \(M\) and \(R\) are the mass and the radius of the solid sphere, respectively, and the gravitational acceleration is \(g=9.8\text{ m/s}^2.\)

A brand new off-road \(6 \times 6\) pickup truck has six wheels. If the total mass of the pickup truck is \(1200\text{ kg}\) and the mass of each of the six wheels is \(19\text{ kg},\) what fraction of its total kinetic energy is due to the rotation of the wheels about their center axles?

Assume that each of the six wheels is a uniform disk.

Consider a situation where a uniform solid sphere, which was rolling smoothly along a horizontal floor, rises up along a \(30.0^\circ\) slope. If it stops after it has rolled \(9.00\text{ m}\) along the slope and then begins to roll backward, what was its initial speed?

The rotational inertia of a solid sphere about any diameter is \(I=\frac{2}{5}MR^2,\) where \(M\) and \(R\) are the mass and the radius of the solid sphere, respectively, and the gravitational acceleration is \(g=9.8\text{ m/s}^2.\)