What does not affect the apparent brightness of a star?

25pts the diagram shows the positions of the sun, moon and earth during spring tides, when the high tides are at their highest and low tides at their lowest. what is it about these positions that causes these high and low tides?

Dc versus ac problem. suppose your dc power supply is set to 15 v and the vertical setting on the oscilloscope is at 5 v/div. how many divisions will the trace deflect if you connect the output of the power supply to the scope with the a input switch set on dc? how many divisions if the switch is on ac?

Aswimmer is determined to cross a river that flows due south with a strong current. initially, the swimmer is on the west bank desiring to reach a camp directly across the river on the opposite bank. in which direction shoud the swimmer head? a. the swimmer should swim southeast. b. the swimmer should swim south. c. the swimmer shuold swim northeast. d. the swimmer should swim due north. e. the swimmer should swim due east.