What's a person code? a. the code stipulating the number of people on your insurance plan b. the code assigned to any employee by his / her employer in the medical field c. the code allocated the family as a unit on the insurance plan, consisting of eight digits d. a unique number allocated to each family member consisting of three digits

Can someone explain to me how to do this problem ?

Mike walks 100 meter north, then walks 30 meters south. after this, he walks another 10 meters north. what is the magnitude of his total displacement during this walk,in meters?

Water is siphoned from a large tank and discharges into the atmosphere through a 50-mm diameter tube. the end of the tube is b = 2.1 m below the tank bottom which is a = 7.4 m deep, and viscous effects are negligible. determine the maximum height h over which the water can be siphoned without cavitation occurring. atmospheric pressure is 101.4 kpa, and the water vapor pressure is 1.79 kpa (absolute)