Jim runs every morning if it takes him 30 minutes at a rate of 0.25 miles/minutes how many miles does Jim run

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?

How can waves travel through ground?

Why do atoms emit energy of only specific wavelengths