Boron, carbon, nitrogen and oxygen are all members of the same what

Gunpowder residue is most likely to show up where on a shooters hands

In positive numbers less than 1, the zeros between the decimal point and a non-zero number are blank significant

You hang a book bag on a spring scale and place the bag on a platform scale so that the platform scale reads 23.7n and the spring scale reads 13.8n. what is the magnitude of the force that earth exerts on the bag?