1. An object appears yellow when viewed with white light. What color would it appear when viewed with green light? 2. An object appears yellow when viewed with white light. What color would it appear when viewed with blue light?

see the picture for the vector

the magnitude of the vector by pythagorean theorem

r = √( (-10)^2 + (3)^2 ) = √109

magnitude = √109 units

the direction angle between vector and x-axis is

tan^(-1)(3/10) = 16.699

so the direction is approximately 16.7 degrees north of west

there are no contact forces mentioned on the list of choices that you've provided.

3. dark matter

empty space could also be a simple vacuum