Which is the role of a compressor in an air conditioner

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.

In a given chemical reaction, the energy of the products is greater than the energy of the reactants. which statement is true for this reaction?

4. if you were an astronaut on the moon, what would you experience? what would you see from your perspective?