Average velocity, displacement vector.

In summary, the car moved 100 km north, turned towards east, and traveled 60 km for 1 h. The average velocity and speed of the car are 53.3 km/h and 13.3 km/h, respectively.
  • #1
Shpat Celiku
11
0

Homework Statement


Suppose that a car moves up north 100 km for 2 h and then turns towards east
and travels in this direction 60 km for 1 h.
a. Draw in the following diagram the displacement vector of the car?
b. Determine the average velocity and the speed of the car.
c. Answer the question (b), if in the second part of the motion the driver would have
traveled the same distance (60 km) for the same time (1 h), but toward south.2. The attempt at a solution
a) No idea.
b) 100+60/2+1=53.3km/h
c) 100-60/2+1=13.3km/h

I'm not sure about any of them.
 

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  • #2
a) This is like a path on a map. Make north "up", south "down" and so on and choose a convenient scale, so you can draw the motion of the car in the graph.
Shpat Celiku said:
b) 100+60/2+1=53.3km/h
I guess you mean (100km+60km)/(2h+1h). This is the average speed. It is not the average velocity.
What is the position of the car after those 3 hours? How far away from its initial position is it?
Shpat Celiku said:
c) 100-60/2+1=13.3km/h
Why did you subtract the 60 here and added them at (b)? The car changed its direction in both cases.
 
  • #3
b) It's 160 km away from its initial position..How can i find the average velocity?

c) Cmon man if i knew how to do it i wouldn't be asking for help :/
 
  • #4
Shpat Celiku said:
b) It's 160 km away from its initial position..
It is not. Did you draw a sketch?
c) Cmon man if i knew how to do it i wouldn't be asking for help :/
I assume you did not blindly put together symbols, so why did you choose the calculations you posted?
 
  • #5
b)100 km north,then 60 km east...the displacement is from 0 to that point?

c) He traveled 100 km north and traveled another 60 back.

I don't know..i'm not very good at this as you can see.Now can you help me please?
 
  • #6
Shpat Celiku said:
b)100 km north,then 60 km east...the displacement is from 0 to that point?
Yes, but how far away is that point if you have a direct connection?

c) He traveled 100 km north and traveled another 60 back.
Okay. But he did not continue to travel 60 in (b).

Now can you help me please?
That's what I am doing here.
 
  • #7
He didn't?..It says he traveled 100 km north, changed direction and traveled another 60 km east.
Isn't average velocity formula : v : displacement/time ?

mfb said:
That's what I am doing here.

I know,i'm sorry.It's just that my deadline is tonight and I'm really stressed.
 
  • #8
Shpat Celiku said:
He didn't?..It says he traveled 100 km north, changed direction and traveled another 60 km east.
Sure, he made a detour. How far would the direct way be?
Isn't average velocity formula : v : displacement/time ?
Yes, and the displacement is the length of the direct way which I asked for.
 
  • #9
I still think it's 160 if it was a straight road :/...Can you explain why it's not and how to find the displacement?
 
  • #10
I attached a sketch you should have already now. Do you really think X is as long as the other two sides together?

car-png.74600.png
 

Attachments

  • car.png
    car.png
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  • #11
X is 80.
so V=80/t...should t be 3 or t final - t initial which i think is 2 ?
 
  • #12
I think it's V=80km/3h=26.6 km/h
 
  • #13
X shorter than the vertical line? No, certainly not.
Many mistakes can be found with cross-checks as simple as that.

What do you mean with t final and t initial? The car needed 3 hours to go from the original point to the final point.
 
  • #14
Well as you can see I'm not getting it.
Can you tell me the value of X?
And then show me how to solve c) because we are both getting tired.
 
  • #15
last try
is X 116.61?
 
  • #17
And in c) is X 40?
 
  • #18
Yes
Shpat Celiku said:
And in c) is X 40?
 
  • #19
Thank you very much:)
 

Related to Average velocity, displacement vector.

1. What is average velocity?

Average velocity is a measure of an object's displacement over a given time interval. It is calculated by dividing the total displacement by the total time taken.

2. How is average velocity different from average speed?

Average velocity takes into account the direction of an object's motion, while average speed only considers the magnitude of its motion. Average velocity is a vector quantity, while average speed is a scalar quantity.

3. How is displacement vector related to average velocity?

Displacement vector is a measurement of an object's change in position, and it is represented by an arrow pointing from the initial position to the final position. Average velocity is calculated by dividing the displacement vector by the total time taken.

4. What is the unit of measurement for average velocity?

The unit of measurement for average velocity is meters per second (m/s) in the SI (International System of Units) system. It can also be expressed in other units such as kilometers per hour (km/h) or feet per second (ft/s).

5. How is average velocity calculated mathematically?

The mathematical formula for average velocity is:
v = Δd / Δt
Where v is the average velocity, Δd is the change in displacement, and Δt is the change in time. This formula can also be written as:
v = (df - di) / (tf - ti)
Where df and di are the final and initial positions, and tf and ti are the final and initial times.

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