A spring scale rests on a horizontal table. Two students pull at opposite ends of the scale, each with a force of 150 N. What is the reading on the spring scale?

Aproton is projected toward a fixed nucleus of charge +ze with velocity vo. initially the two particles are very far apart. when the proton is a distance r from the nucleus its velocity has decreased to 1/2vo. how far from the nucleus will the proton be when its velocity has dropped to 1/4vo?

Glass has a hardness that is in the middle of the hardness scale. what is the hardness of glass?

Convection occurs when thermal energy is transferred by the movement of