Discuss the changes in potential energy, kinetic energy, and total energy for a skateboarder going up and down on a half-pipe (u-shaped) ramp. specifically address the energies when the skater is at the highest point (a), half-way down the ramp (b), and at the lowest point (c).

In a good thermo flask the main cause of heat loss is

Asolid cylinder and a cylindrical shell have the same mass, same radius, and turn on frictionless, horizontal axles. the cylindrical shell has light-weight spokes connecting the shell to the axle. a rope is wrapped around each cylinder and tied to blocks of equal masses that are held the same height above the ground. both blocks are released simultaneously. the ropes do not slip. which block hits the ground first? or is it a tie?

When using the scientist method, which step comes last?