Question

Difficulty: HardDirection and Distance Test

An autonomous security robot at an industrial facility begins its inspection patrol from central gate OO facing East. It moves 14 m14\text{ m} due East to reach checkpoint AA. From checkpoint AA, it turns 135135^\circ anti-clockwise and travels 102 m10\sqrt{2}\text{ m} to checkpoint BB. At checkpoint BB, it turns 9090^\circ clockwise and travels 52 m5\sqrt{2}\text{ m} to checkpoint CC. Next, it turns 9090^\circ anti-clockwise and travels 42 m4\sqrt{2}\text{ m} to reach checkpoint DD. Finally, it turns to face due South and moves 7 m7\text{ m} to reach its final parking dock EE. What is the shortest straight-line distance (in meters) between central gate OO and final parking dock EE?

Answer: 13 m

Answer

The shortest straight-line distance between central gate OO and final parking dock EE is 13 m13\text{ m}.
By resolving each directional move into its respective orthogonal (x,y)(x, y) components, the cumulative net position of the robot from origin O(0,0)O(0, 0) is found to be (5,12)(5, 12). Applying the distance formula gives 52+122=169=13 m\sqrt{5^2 + 12^2} = \sqrt{169} = 13\text{ m}.

Step-by-Step Solution

1
Establish Cartesian Coordinates
Central gate O=(0,0)O = (0, 0), with +x+x as East, x-x as West, +y+y as North, and y-y as South.
Cartesian representation allows precise vector addition for multi-directional paths.
2
Calculate displacement to checkpoint A
Displacement is (14,0)(14, 0), so A=(14,0)A = (14, 0).
The robot travels 14 m14\text{ m} directly East along the positive x-axis.
3
Calculate displacement to checkpoint B
Displacement vector is (10,10)(-10, 10), so B=(4,10)B = (4, 10).
Turning 135135^\circ anti-clockwise from East points North-West (135135^\circ). Distance 102 m10\sqrt{2}\text{ m} gives Δx=10212=10\Delta x = -10\sqrt{2}\cdot\frac{1}{\sqrt{2}} = -10 and Δy=10212=10\Delta y = 10\sqrt{2}\cdot\frac{1}{\sqrt{2}} = 10.
4
Calculate displacement to checkpoint C
Displacement vector is (5,5)(5, 5), so C=(9,15)C = (9, 15).
Turning 9090^\circ clockwise from North-West points North-East (4545^\circ). Distance 52 m5\sqrt{2}\text{ m} gives Δx=5\Delta x = 5 and Δy=5\Delta y = 5.
5
Calculate displacement to checkpoint D
Displacement vector is (4,4)(-4, 4), so D=(5,19)D = (5, 19).
Turning 9090^\circ anti-clockwise from North-East points North-West (135135^\circ). Distance 42 m4\sqrt{2}\text{ m} gives Δx=4\Delta x = -4 and Δy=4\Delta y = 4.
6
Calculate displacement to final dock E
Displacement vector is (0,7)(0, -7), so E=(5,12)E = (5, 12).
Moving 7 m7\text{ m} due South reduces the y-coordinate by 77.
7
Compute shortest straight-line distance OE
Distance OE=52+122=169=13 mOE = \sqrt{5^2 + 12^2} = \sqrt{169} = 13\text{ m}.
Apply the Pythagorean theorem to net displacement components x=5x = 5 and y=12y = 12.

Key Concept

Vector Addition of Angular Displacements and Pythagorean Theorem
Estimated Time:2m 0s
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