Please help I am very confused and will like an answer for both please

where's the following? you gotta add it to know what the choices are

explanation:

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

conservation of mass

mass before something happens = mass afterwards