What is the ratio of the electrical force to the gravitational force between an electron and a positron?

Afrequency generator sends a 550 hz sound wave through both water and ice. what is the difference in wavelength between the wave produced in ice and the wave produced in water?

The magnitude of the amount of energy released by burning a fuel source, measured in energy per unit mass, is called its fuel value. note that the fuel value is the negative of the isobaric specific heat of combustion for the fuel. if all the energy obtained from burning 1.23 pounds of butane with a fuel value of 10.85 kcal/g is used to heat 128.0 kg of water at an initial temperature of 18.3 °c, what is the final temperature? note that 1 lb = 453.6 g.

Ascientific blank must be testable and capable of being proven false?