Why does an aerial firework require two explosions of black powder

The diagrams show objects’ gravitational pull toward each other. which statement describes the relationship between diagram x and y? gravity attracts only larger objects toward one another. gravity attracts larger objects only if they are close to one another. if the masses of the objects increase, then the force between them also increases. if distance between the objects increases, then the amount of force also increases.

In science class richard learns that a substance has a boiling point of 230 fahrenheit his teacher ask him to convert this temperature to degrees celsius what is the boiling point of his substance in degrees celsius

The kw for water at 0 °c is 0.12× 10–14 m2. calculate the ph of a neutral aqueous solution at 0 °c.