When designing an experiment how do you choose a system to investigate

What color would an object that reflects green and blue light appear to be in white light? a. blue b. cyan c. magenta d. black

An engineer designs a roller coaster so that a car travels horizontally for 162 ft, then climbs 127 ft at an angle of 31.0° above the horizontal. it then moves 127 ft at an angle of 46.0° 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.)

Acar is traveling 35 mph on a smooth surface . if a balanced force is applied to the car what happens?