What is the mass of an object if it is moving at a speed of 10 m/s and has 400 J of kinetic energy?

Hydrogen and helium are both members of?

Will mark as brainliest how does a catapult increase the trajectory of an object? ps. answer as if u were a 5th grader

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?