1) you are building a model plane that needs small block inside to balance its weight. you find that the block material you are using has half the density you thought it did. you still need the same weight for the blocks in the plane, and they must have the same width and length. how you can keep the weight the same? 2) your teachers set two cups on a bench at the front of the class. one contains water dyed blue and the other clear water. the teacher says one cup is very salty water and the other one is freshwater. how would you figure out which one is salty and which one is fresh.

3) In much of the world, SI units are used everyday life and not just in science. why would it make sense for people in the united states to use SI in everyday life, too? explain using math terms such as calculate and convert.

HELP ME PLEASEE