Will our sun ever undergo a white dwarf supernova explosion? why or why not?

a) no, because it is not orbited by another star.
b) no, because the sunʹs core will never be hot enough to fuse carbon and other heavierelements into iron.
c) yes, about a million years after it becomes a white dwarf.
d) yes, right at the end of its double-shell burning stage of life.

Atrain departs from its station at a constant acceleration of 5 m/s. what is the speed of the train at the end of 20s?

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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?