A boat's engine pushes it east with 300 newtons while a current pushes it north with 400 newtons. What is the magnitude of the resultant force?

Correct answer to question 113 (Mechanical Comprehension): 500 newtons

Method

Perpendicular forces combine as the hypotenuse of a right triangle: the square root of (300^2 + 400^2) = 500 newtons.