Answer:
Dry lubricants or solid lubricants are materials that, despite being in the solid phase, are able to reduce friction between two surfaces sliding against each other without the need for a liquid oil medium.
Explanation:
It took so long because at the time there was no way for people to study the behavior formally. im not sure what helped it get recognized but i know wihelm wundt helped get it recongnized.
sorry i couldnt be much help
Answer:
Specific gravity for liquids is nearly always measured with respect to water at its densest
Explanation:
Density I'm not sure
volume unchanged
mass unchanged
shape- water