Which forces do not require contact between objects in order to exert a push or pull?
select all that apply

gravitational force between the earth and an object

tension force between an object and a rope

magnetic force between two magnets

frictional force between a surface and an object

gravitational force between the earth and an object and magnetic force between two magnets

Explanation:

gravitational force between the earth and an object and magnetic force between two magnets are forces that does not require contact between objects in order to exert a push or pull.

The earth and the object are never in contact with each other but there is a force of gravitation existing between them. There is force of attraction between the masses of the earth and the masses according to gravitational law are separated by a distance.

Force between two magnets may or maynot exert push or pull. They only attract when the poles of the magnets are unlike poles (different). There is force of repulsion between them if like poles of the magnet come together according to the law of magnetism. Magnets in magnetic field will always experience force even if at a distance from each other in the field hence the reason for the selected options

.) the observation by semmelweis that more mothers died of childbed fever when their doctors also worked in the morgue