Look at the velocity vs. time graph. During which time interval is the cart moving up the track while freely rolling?

An object weigh 40n in air ,weigh 20n when submerged in water, and 30n when submerged in a liquid of unknown liquid density. what is the density of unknown of liquid?

Patricia is trying to compare the average rainfall of new york to that of arizona. a comparison between these two states for the months of july through september would best be measured in

Scientists follow specific processes in order to determine valid explanations and conclusions from observations. david observed strange lights in the sky above his home outside of roswell, new mexico. the only explanation that makes sense to him is that there are ufos in the area. what should david do next to verify his explanation?