# Displacement and Average Velocity of a Whale

• Turquoise
In summary, the whale swims 8 km due east, 2 km west, and 4 km due east in a total of 16 km. Its displacement is 8 km and its average speed is 3.5 km/hr.
Turquoise

## Homework Statement

A whale swims due east for a distance of 8.0 km in a time of 2.50 hours. It then turns around and moves west for 2.0 km on a time of 0.50 h. It turns around again and heads 4.0 km due east in a time of 1.00h.

## Homework Equations

a. What is the total distance traveled by the whale?
b. What is the total displacement?
c. Calculate the average speed for the entire trip.
d. Calculate the average velocity for the entire trip.

## The Attempt at a Solution

I only got a and c correct, for a I put 14 Km and for c I put 3.5 km/ hr. I tried to do the question again and I drew out the whale swimming, and guessed that the displacement is 8 Km. This was a previous test, and the teacher didn't go over it! I'm trying to study for my exam ;). Thanks.

The total displacement is the final position minus the initial position. So,

Total displacement = 8 km - 2 km + 4 km.

Think of the displacements as vectors then add these vectors.

The average velocity is the total displacement divided by the total time traveled.

Chrisk, it wouldn't be 8 km?

Because the whale goes east 8 and then west 2 and then east 4.

But, I could be wrong! I don't understans displacement all that well. So, can you clarify? TY!

Think of total displacement as the final stopping point minus the starting point. For example, you tell someone who is a room with you that you are going to the store down the street. That person leaves the room before you go to the store. You arrive back from the store empty handed and find the person is not in the room. A little while later, the person enters the room and asks if you went to the store. You say you did but that person says you didn't go anywhere because you are at the starting point. So, your total displacement is zero! If this person happened to see you standing just outside the room talking to someone after you went to the store, that person would think you only moved from the room to just outside the room.

Turquoise said:
Chrisk, it wouldn't be 8 km?

Because the whale goes east 8 and then west 2 and then east 4. But, I could be wrong! I don't understans displacement all that well. So, can you clarify? TY!

Please explain how are you getting 8? It will tell us what your confusion is.

displacement: final position - initial position
Nothing in between matters.

You are at your house and you are going to get coffee from starbucks. You want the displacement from your house to starbucks.
Its also easier to look at them on a number line

-5 -4 -3 -2 -1 0 1 2 3 4 5
----------------------------------------------------------
Let say your house is your initial (starting) and its located at 1
Starbucks is your final and its located at 3
As you can see starbucks is very close to your house since they are everywhere
You get out of your house and you head west for 2 miles and you reach starbucks. You're there

Now the math 3-1=2 miles

On the other hand let say you are going to starbucks. You go 3 miles East to pick up your 1st friend, You go another 1 mile to pick up your other friend and then you all go to starbucks together.

-5 -4 F F -1 0 H 2 S 4 5
----------------------------------------------------------

the 3 and the 1 miles you went to drive your friend don't matter. Its still final - initial
3-1 and your displacement is still 2 miles.

Hope that helps out a little bit. I should warn you though. The negatives on the number line are not always on the left.

it could be backwards

5 4 3 2 1 0 -1 -2 -3 -4 -5
---------------------------------
-------------------------

## What is displacement?

Displacement is the change in position of an object from its initial position to its final position. It is a vector quantity, meaning it has both magnitude and direction.

## How do you calculate displacement?

To calculate displacement, you subtract the initial position of an object from its final position. The resulting value is the displacement, which can be positive, negative, or zero depending on the direction of motion.

## What is average velocity?

Average velocity is the rate of change of displacement over time. It is a vector quantity that describes both the speed and direction of an object's motion.

## How do you calculate average velocity?

To calculate average velocity, divide the displacement of an object by the time it took to travel that distance. The resulting value is the average velocity, which is typically measured in units of distance per time (e.g. meters per second).

## How is displacement and average velocity of a whale measured?

The displacement and average velocity of a whale can be measured using various methods such as satellite tracking, acoustic tracking, and visual observation. These methods involve recording the whale's movements over a specific period of time and using mathematical calculations to determine its displacement and average velocity.

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