Math Problem Statement

Pall walks 4 m to the west, then 8 m north, and lastly 6 m east. What is his resultant displacement?

Solution

We can solve this problem by determining Pall's final position relative to his starting point, which will give us his resultant displacement.

Step 1: Break the movement into coordinates

Assume Pall starts at the origin (0,0)(0, 0).

  • First, he walks 4 m west, which is in the negative x-direction. His new position is (4,0)(-4, 0).
  • Next, he walks 8 m north, which is in the positive y-direction. His new position is (4,8)(-4, 8).
  • Lastly, he walks 6 m east, which is in the positive x-direction. His new position is (2,8)(2, 8).

Step 2: Use the Pythagorean theorem to find the resultant displacement

The displacement is the straight-line distance from the starting point (0,0)(0, 0) to the final position (2,8)(2, 8). We can calculate this using the formula for the distance between two points:

Displacement=(x2x1)2+(y2y1)2\text{Displacement} = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2}

Substitute the coordinates (x1,y1)=(0,0)(x_1, y_1) = (0, 0) and (x2,y2)=(2,8)(x_2, y_2) = (2, 8):

Displacement=(20)2+(80)2\text{Displacement} = \sqrt{(2 - 0)^2 + (8 - 0)^2} Displacement=22+82\text{Displacement} = \sqrt{2^2 + 8^2} Displacement=4+64=68\text{Displacement} = \sqrt{4 + 64} = \sqrt{68}

Displacement8.25m\text{Displacement} \approx 8.25 \, \text{m}

Step 3: Direction of the displacement

The angle of the displacement can be found using the inverse tangent function:

θ=tan1(oppositeadjacent)=tan1(82)=tan1(4)\theta = \tan^{-1} \left(\frac{\text{opposite}}{\text{adjacent}}\right) = \tan^{-1} \left(\frac{8}{2}\right) = \tan^{-1}(4)

θ75.96north of east.\theta \approx 75.96^\circ \, \text{north of east}.

Thus, Pall's resultant displacement is approximately 8.25 meters at an angle of 75.9675.96^\circ north of east.

Do you need more details or have any questions?


Here are 5 related questions:

  1. What if Pall walked 10 m south instead of 8 m north?
  2. How would the displacement change if Pall walked west first, then north and south?
  3. Can you find Pall's average velocity if this trip took 10 seconds?
  4. What would be Pall’s resultant displacement if he also walked 5 m south after his last movement?
  5. How do we calculate displacement in three-dimensional movement?

Tip: When dealing with displacement, always consider the direction since displacement is a vector quantity!

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Math Problem Analysis

Mathematical Concepts

Vector Displacement
Pythagorean Theorem
Trigonometry

Formulas

Displacement = sqrt((x2 - x1)^2 + (y2 - y1)^2)
θ = tan^(-1)(opposite/adjacent)

Theorems

Pythagorean Theorem
Trigonometric Ratios

Suitable Grade Level

Grades 9-10