Who's in highschool? lol, it said ask a question

Which system of units is used by only a small number of countries in the world, including the u.s.

The electric field inside a cell membrane is 8.0mn/c. what's the force on a singly charged ion in this field?

An airplane is flying with a velocity of 240 m/s at an angle of 30.0∘ with the horizontal, as the drawing shows. when the altitude of the plane is 2.4km,a flare is released from the plane. the flare hits the target on the ground. what is the angle θ?