If I stare at a green square on a red background for a long time and then I stare at a white wall: do I see: 1.a red square on a green background.
2.a red square on a black background.
3.a green square on a white background.
4.a white background, as the figure and background cancel each other

it should be -8.6 cm hope this out

igneous rocks also form where plates converge. the subducting plate melts as it sinks into the crust of the earth, and the melt rises into the overriding plate forming volcanoes. metamorphic rocks are formed mainly in the lithosphere, wherever there is high pressure and high temperature. -woods

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

t = 1/400 h   ⇔ 0.0025 h ⇔ 9s ⇔ 0.15 m

any of the answers are correct.