Which ferromagnesian mineral is believed to constitute up to 50% of the mantle?

it is true because as we rotate around the way we rotate makes day come and because the moon is rotating around the earth that's what makes it night come. hope this .

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