A mouse runs 5 m north across the floor before hearing a cat. Then it runs back south along the same

path for 1 m and turns west to run under a sofa 3 m away. What is the displacement of the mouse and
the total distance it ran? (1 point)

The mouse's displacement is 5 m southwest and it ran 9 m.

The mouse's displacement is 9 m and it ran 5 m.

The mouse's displacement is 0 m and it ran 9 m.

The mouse's displacement is 5 m northwest and it ran 9 m.

1 answer

To find the displacement of the mouse and the total distance it ran, let's analyze the movements step-by-step.

  1. Initial Movement (North): The mouse runs 5 meters north.
  2. Second Movement (South): The mouse then runs back 1 meter south. The net northward movement is \(5 m - 1 m = 4 m\) north.
  3. Third Movement (West): Finally, the mouse runs 3 meters west.

Now, to calculate the total distance run, we sum all the distances traveled:

  • First leg: 5 m (north)
  • Second leg: 1 m (south)
  • Third leg: 3 m (west)

Total distance = \(5 m + 1 m + 3 m = 9 m\).

Next, we calculate the displacement, which is the straight-line distance from the starting point to the endpoint. The mouse is now 4 m north and 3 m west of its starting point.

Using the Pythagorean theorem to find the displacement:

\[ \text{Displacement} = \sqrt{(4 m)^2 + (3 m)^2} = \sqrt{16 + 9} = \sqrt{25} = 5 m. \]

To determine the direction of the displacement, we can use trigonometry:

  • The angle \(\theta\) can be found using:

\[ \tan(\theta) = \frac{\text{opposite}}{\text{adjacent}} = \frac{3 m}{4 m}. \]

The angle points in the northwest direction since the mouse is north but also moves west. Therefore, the displacement is 5 m in the northwest direction.

In summary:

  • The total distance the mouse ran is 9 m.
  • The displacement of the mouse is 5 m northwest.

Based on the options provided: The mouse's displacement is 5 m northwest and it ran 9 m.