Is half the size of earth, has two moons, and has an atmosphere of mostly carbon dioxide

Two particles of masses m and 2m are placed on a smooth horizontal table. a string, which joins these two masses, hangs over the edge supporting a pulley, which suspends a particle of mass 3m. the pulley has negligible mass. the two parts of the string on the table are parallel and perpendicular to the edge of the table. the hanging parts of the string are vertical. find the acceleration of the particle of mass 3m.

The diagram shows a series of volcanic island and a hot spot determine the direction of movement of the tectonic plate that for the island

Where should a carbon monoxide detector be mounted?