Why does physics require extensive use of vectors as compared to just scalar quantities?

part 1: describe the mass and the surface temperature of dwarf stars.

part 2: explain using complete sentences where on the hr diagram you would expect to find a dwarf star based on its physical properties.

part 1: the mass of a dwarf star is very small and the surface temperature of dwarf stars are high and they have the lowest absolute brightness.

part 2: on the hr diagram you would expect to find a dwarf star based on its physical properties at an absolute brightness of -2 to -4

hope this