Help me plz I need the answers

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.

1.what is where an object is located 2. what is how fast an objects speed is changing 3. what is how fast an object is moving

If the chemical properties of a substance remain unchanged and appearance or shape of a substance changes it is called a ?