In the context of vectors and scalars, what is the key difference between speed and velocity?

Which of the following graphs best represents the vector field $F=kr$, where $k$ is a positive constant and $r$ is the position vector from the origin?

A force of magnitude $10$ $N$ acts at an angle of $30°$ above the positive $x$-axis in the $xy$-plane. How can this force be expressed as a Cartesian vector?

A person walks $4$ km east and then $3$ km north. What is the magnitude of the resultant displacement from the starting point?

Which of the following best describes the direction of the vector field $f(x,y)$ = $\frac{yi-xj}{x^2+y^2}$ at any point (x, y) in the plane?