A student rides a bicycle 240 meters in 4 minutes to get to school what is the student's speed?

The chart shows the bid provided by four contractors to complete a job. which contractor is the most cost-effective?

Diffraction is when light is bent around obstructions. which of the these observation about clouds would indicate diffraction? a) after rain storms, you can sometimes see rainbows. b) clouds are white or gray and cannot be seen through. c) on a cloudy day, the temperature tends to be cooler than a sunny day. d) the edges of dark clouds appear lighter. this

Hey guys so i need to know what is _nh3+> nh4oh ~chemistry~