Atrain travels 120 km in 2 hours and 30 minutes what’s its average speed

Imagine that someone pushes one marble toward a motionless marble. would there still be action-reaction forces involved in the collision? how might the marbles’ motions be changed? ?

Juan created a chart to him study for a test. which headings best complete the chart? x: transparent objects y: opaque objects x: opaque objects y: transparent objects x: high frequency waves y: low frequency waves x: low frequency waves y: high frequency waves

Ihave a density of 1.61g/cm^3 and a mass of 28g. find the missing value