Question

a cow walks 2.4 km due east of her starting point. she then turns around and walks back 1.1 km due west. after this, she turns back around and walks 3.3 km due east and finally stops.
what is the distance that she has walked?
what is her displacement?

Explanation:

Step1: Calculate the total distance walked

The total distance is the sum of all the individual distances walked.
$$2.4 + 1.1+3.3$$

Step2: Calculate the displacement

Let east be the positive direction.
First displacement: \(d_1 = + 2.4\) km (east)
Second displacement: \(d_2=-1.1\) km (west)
Third displacement: \(d_3 = + 3.3\) km (east)
The total displacement \(D=d_1 + d_2 + d_3\)
$$D=2.4-1.1 + 3.3$$

Answer:

• Distance walked: \(2.4+1.1 + 3.3=6.8\) km
• Displacement: \(2.4-1.1+3.3 = 4.6\) km east