20. A bullet is fired vertically upward from a gun and reaches a height of 7000 ft. (a) Find its initial velocity. (b) How long does it take to reach its maximum height?
(c) How long is it in flight?

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