What is the momentum of a 47-gram tennis ball that is traveling at 40 m/s

Ineed with these last two questions: 1) what are two types of cold air masses that influence the weather in north america? name them and describe their humidity. 2) describe the motion of a cold air mass and a warm air mass and the weather you would expect at a warm front and an occluded front.

What property is a characteristic of a substance that can be observed and does not change the identity of the substance

Why do different substances have diffrent properties