Which characteristic accounts for the fact that red lights in dark rooms and DO NOT expose negatives during developing?

Acurve connects the data points that are plotted. (physical science chapter 11 motion)

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?

Which of these metals are magnetic?