What is the mass of an atom with six protons, seven neutrons, and eight electrons?

The free body diagram shows a box being pulled to the left up a 25-degree incline. the magnitude of the normal force is

Which lists the fundamental forces in order, from strongest to weakest? strong nuclear, weak nuclear, electromagnetic, gravitational strong nuclear, electromagnetic, weak nuclear, gravitational gravitational, weak nuclear, electromagnetic, strong nuclear electromagnetic, gravitational, strong nuclear, weak nuclear

Why is it important always to use horizontal bars in unit fractions when performing unit conversions?