A horizontal force of 50 N causes a trolley to move a horizontal distance of 30M How much work is done on the trolley by the force?

Which term best describes the phrase “something that happens”?

Hydrogen and helium are both members of?

I'm thinking it's 2 you are asked to explain the earth's magnetic field. which is the best reply? 1. the earth's magnetic south is similar to the north pole of a magnet. 2. the earth's core has a strong magnetic charge similar to the south pole of a magnet. 3. the earth's geomagnetic south is similar to the south pole of a magnet. 4. the earth's magnetic charge is not centered at either pole; it varies based on location.