Which phrases describe a model in science? check all that apply.

a structure that represents a very small system

something that is an example of a very large object

a structure that is used to represent a complex system

several structures that always represent different things

something that is unique and gloes not imitate an object

Model is best described by a structure that is used to represent complex system and something that is example of very large object. So, the second and third phrases best describe model in science.

Option B and C

Explanation:

Science works with complex systems and structures which are difficult to understand and their phenomenon are also complex. So science uses models or assumptions setting some boundary conditions to understand and solve the problems easily.

Just like liquid drop model explains the fission and fusion reaction occurring in the nucleus of atoms easily and the models are also used to remember the significance and mechanism of a complex system. Just like shell model describes easily the arrangement of electrons in different shell.

Models are also used as an example of something that is very big or very small like planetary model for the big universe or the atomic model which is not visible in naked eye. So the second and third phrases among the other phrases given, best describe model in science.

can be answered using momentum.

momentum = p

p1= mass1 * velocity1

p1 = p2

therefore

p1 = 6kg * 4m/s

p1 = 24kgm/s

p2=m2 * v2

24 kgm/s = 7kg * v2

v2 = 24 kgm/s / 7kg

v2= 3.42 m/s