Friction opposes the movement of the crate across the warehouse foor Does the frictional force change or stay the same as the crate gets heavier?

Idon’t quite understand this problem

Describe the function of the endomembrane system? what organelles are involved?

Four objects each with charge +2.0×10−7c are located at the corners of a square whose sides are 2.0 m long. part a what quantities can be determined using this information? check all that apply. the electric force on a charged object placed at the center of the square. the mass of each object. the total electric potential energy of the system consisting of the four charged objects. part b find the electric force on a charged object placed at the center of the square.