Why does the chemical reaction seen here obey the law of conservation of matter?

The a metal retainer that keeps the rolling elements evenly spaced. n a. seal n b. separator n c. bearing n d outer race

An engineer designs a roller coaster so that a car travels horizontally for 152 ft, then climbs 137 ft at an angle of 34.0° above the horizontal. it then moves 137 ft at an angle of 48.0° below the horizontal. if we take the initial horizontal motion of the car to be along the +x-axis, what is the car's displacement? (give the magnitude of your answer, in ft, to at least four significant figures and give the direction of your answer in degrees counterclockwise from the +x-axis.)

Why does lightning travel from clouds to the ground?