Which of the following displacement vectors (if any) are equal?
vector magnitude direction
a 100 m 30° north of east
b 100 m 30° south of west
c 50 m 30° south of west
d 100 m 60° east of north

b andc
a, b, and d
a andd
none are equal

Animals respond in various ways to stimuli detected through their senses. some of these responses are stimulated by the presence of danger. which of these animal responses is the best example of a response to an immediate threat? a) a rooster crows every morning at the first sign of light. b) as something approaches an octopus, it shoots a cloud of ink. c) from late fall until spring, bears hibernate to preserve energy. reactivate d) a dog is getting hot in the sunlight, so he moves to a shaded area.

What are similarities and differences between refraction, reflection, diffraction and absorption?

Hydrogen and helium are both members of?