Why did they meet their friend

For positive constants a and b, the force between two atoms in a molecule is given f(r) = −a r2 + b r3 , where r > 0 is the distance between the atoms. note: a and b are upper case letters. (a) find f '(r) = (b) find the critical point for f(r). r = (c) find f ''(r) = (d) find the value of r so that f ''(r) = 0.

What are "open-loop" and "closed-loop" systems

Evaluate the scenario below and indicate how to handle the matter appropriately. situation: michael received an e-mail from what he thought was his doctor’s office, requesting his social security number. since he had just been in to see his doctor last week, he replied to the e-mail with his social security number.