In solving a physics problem, why is it important to create pictorial and physical models before trying to solve an equation?

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.

Alice added sodium chloride to water and stirred the water for several minutes. alice is most likely trying to demonstrate that ionic compounds a. are hard. b. can dissolve. c. are clear. d. can melt.

The law of conservation of energy states that energy cannot be created or , energy can be from one substance to another. the first blank is ' destroyed ' and for the second blank is ' transferred '