drives 7 km, turns right and drives 5 km. He then takes a left turn and drives 9 km. He
takes a final right turn, drives 7 km and stops at Point P. How far (shortest distance) and
towards which direction should he drive in order to reach Point A again? (All turns are
$90^{\circ}$ turns only unless specified.)
This problem requires us to find the shortest distance and direction from Shyam's final location (Point P) back to his starting point (Point A). We can track his journey using coordinates, assuming Point A is the origin (0,0) on a standard map grid, where East is the positive x-axis and North is the positive y-axis.
Shyam's journey can be broken down as follows:
So, Shyam's final position P is at coordinates (14, 2) relative to his starting point A (0,0).
The net displacement from A to P combines movements along the East-West (x-axis) and North-South (y-axis) directions:
Therefore, Point P is located 14 km East and 2 km North of Point A.
To return to Point A (0, 0) from Point P (14, 2), Shyam must travel the displacement vector PA. This vector is calculated as the coordinates of A minus the coordinates of P:
Vector PA = A - P = $ (0 - 14, 0 - 2) = (-14, -2) $
This vector signifies that Shyam needs to travel 14 km towards the West (negative x-direction) and 2 km towards the South (negative y-direction) from Point P to get back to Point A.
The shortest distance between two points is the magnitude (length) of the displacement vector connecting them. We use the distance formula, derived from the Pythagorean theorem:
Distance $ = \sqrt{(\Delta x)^2 + (\Delta y)^2} $
Here, $ \Delta x = -14 $ km and $ \Delta y = -2 $ km.
Distance $ = \sqrt{(-14)^2 + (-2)^2} $
Distance $ = \sqrt{196 + 4} $
Distance $ = \sqrt{200} $ km
To simplify the radical:
Distance $ = \sqrt{100 \times 2} = \sqrt{100} \times \sqrt{2} = 10\sqrt{2} $ km
Calculating the approximate numerical value: $ 10\sqrt{2} \approx 10 \times 1.414 = 14.14 $ km.
The displacement vector for the return journey is PA = \( (-14, -2) \). The negative component in the x-direction indicates West, and the negative component in the y-direction indicates South. Therefore, the direction from P back to A is South-West.
Based on the detailed step-by-step analysis of Shyam's movements, the shortest distance required to return to Point A from Point P is \( 10\sqrt{2} \) km (approximately 14.14 km), and the direction is South-West.
Comparing this calculated result with the options provided:
It appears that none of the provided options accurately match the calculated shortest distance and direction derived from the problem description.