Chapter 11 - Vectors and Vector-Valued Functions - 11.3 Dot Products - 11.3 Exercises - Page 789: 41

$W= 400$ $J$

$|\textbf{F}| = \sqrt {30^2 + 40^2} = \sqrt {2500} = 50$ $N$ $\theta = arctan(\frac{F_y}{F_x}) = arctan(\frac{30}{40}) = 36.8699^\circ$ $W= |\textbf{F}||\textbf{d}|cos(\theta) = (50)(10)(cos(36.8699^\circ)) = 400$ $J$