You are to select the material for the design of a smart phone case (back case that is attached on phone, not additional case)
1. select 3 materials that you think are best : one metal, one polymer and one carbon fibre composite.
2. speicfy the details of the exact material grade selected for each of the three material variations of the smart phone case(specify the resin type).
3. what would be the best choice of material for the phone case from the three options?

Astudent pours 10.0 g of salt into a container of water and observes the amount of time it takes for the salt to dissolve. she then repeats the process using the same amounts of salt and water but this time she slowly stirs the mixture while it is dissolving. the student performs the experiment one more time but this time she stirs the mixture rapidly. the dependent variable in this experiment is: time for salt to dissolve speed of stirring amount of water mass of salt