Which of the following elements is stable? a. boron, atomic number 5 b. fluorine, atomic number 9 c. carbon, atomic number 6 d. neon, atomic number 10

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

Select all the correct answers. which changes will increase the rate of reaction during combustion? decreasing the area of contact between the reactants adding more oxygen to the reaction removing heat from the reaction changing the reactants from solid form to powdered form lowering the exposure of the reactants to air

Figure shows a simple cathode-ray tube. a beam of particles, emitted by the cathode, strikes the centre of the screen.a. why the cathode must be heated? b. what is the principal energy change that occurs when the beam strikes the screen? c describe and explain what you would expect if the two deflecting plates g and h were connected to an alternating voltage supply