a ball is thrown horizontally from the roof of a building 9.0 m tall and lands 8.5 from the base. what was the ball's initial speed?

The slope of a good speed time indicates ? a. velocity b. acceleration c. direction d. speed

Starting with only the balmer series light (visible light), how could we ensure that the solar panels generate a current that mark can use for his power station? a)by gradually increasing the brightness (amount) of light that we shine on it. b)by gradually increasing the frequency of the light we shine on it. c)by gradually increasing the wavelength of the light that we shine on it.

We have a colorless transparent liquid. it looks like water. we seperated it into a solid and a liquid by evaporration and condention was this a chemichal or a physical seperation a. chemical seperation b. physical seperation