Convection currents form when warm air rises and cold air sinks. What causes the warm air to rise and the cold air to sink? difference in weather
difference in climate
difference in density
none of the above

Asmall 21 kilogram canoe is floating downriver at a speed of 1 m/s. what is the canoe's kinetic energy?

In a simplified model of the human eye, the aqueous and vitreous humors and the lens all have a refractive index of 1.40, and all the refraction occurs at the cornea, whose vertex is 2.60 cm from the retina. what should be the radius of curvature of the cornea such that the image of an object 40.0 cm from the cornea’s vertex is focused on the retina?

Astudent weighing 700 n climbs at constant speed to the top of an 8 m vertical rope in 10 s. the average power expended by the student to overcome gravity is most nearly