Question

Dr. Suarez walks 2.8 km north to get to an observation post, then walks 5.1 km south back to her outpost. Determine her distance.

A.) 2.3 km, north

B.) 7.9 km, south

C.) 7.9 km

D.) 2.3 km

Answer 1

C.) 7.9 km

Step-by-step explanation:

Distance and Displacement

An object who constantly travels for some distances at defined periods of time has a total distance as the sum of each individual distance the object traveled. It can be written as:

dtotal=d1+d2+d3+...+dn

This sum is obtained independently of the direction the object moves.

The displacement only takes into consideration the initial and final points of the path defined by the object in its moving. The displacement, unlike distance, is a vectorial magnitude and can be even zero if the object starts and ends the movement at the same point.

Dr. Suarez walks 2.8 km north and then 5.1 km south. The total distance is simply the sum of both distances: 2.8 km + 5.1 km = 7.9 km.

Note the distance does not have any direction (north or south), it's just the number.

Answer: C.) 7.9 km