In this case yes, but if q1 was -20μC, q2 was 30μC, and r was 0.5m, then using -20μC as it is would make F equal to -21.6N which is just 21.6N of attraction force between the two charges.
If you have two charges q1 and q2, you can get the force between them F by multiplying them with the coulomb constant K (approximately 9 × 10^9) and then dividing that by the distance between them squared r^2.
q1 and q2 cannot be negative. Sometimes you'll not be given a charge, and instead the problem will tell you that you have a proton or electron, both of them have the same charge (1.6 × 10^-19 C), but electrons have a negative charge.
Do you even know what the rest of the people on the tracks will do if you stop the trolley? You will be responsible for what happens to the trolley operators and passengers.
Darn, I promoted Lemmy and KBin on Reddit, Voted for mods to continue the protest, encouraged people to request their data from Reddit, and linked my KBin in my bio before completely leaving the platform.
I don't even care about the API prices and I used to use the official Reddit mobile app before migrating.
I've been looking for an open source Reddit like platform since the Twitter drama started and people started migrating to Mastodon, but there wasn't much content on them, until now, so I jumped on the band wagon.