Average acceleration using vectors

In summary, the problem involves a cyclist's motion from one point to another in 14 seconds, with changing velocities in different directions. To find the average acceleration, the velocities must be written in vector form and subtracted to get the net acceleration. The correct answer is 1.37, and the individual accelerations in the east-west and north-south directions can also be calculated.
  • #1
jperk980
47
0
At one instant a bicyclist is 30 m due east of a park's flagpole, going due south with a speed of 18 m/s. Then, 14 s later, the cyclist is 45 m due north of the flagpole, going due east with a speed of 9 m/s. For the cyclist in this 14 s interval, find each of the following.
A)average acceleration

What i did was, i used the fact that a=v/t. So i pluged in a=(9+(-18))/14. The acceleration I got was 1.93. that is the wrong answer. Can someone please tell what i did wrong and help me figure out a way to get the angle. thank You
 
Physics news on Phys.org
  • #2
jperk980 said:
At one instant a bicyclist is 30 m due east of a park's flagpole, going due south with a speed of 18 m/s. Then, 14 s later, the cyclist is 45 m due north of the flagpole, going due east with a speed of 9 m/s. For the cyclist in this 14 s interval, find each of the following.
A)average acceleration

What i did was, i used the fact that a=v/t. So i pluged in a=(9+(-18))/14. The acceleration I got was 1.93. that is the wrong answer. Can someone please tell what i did wrong and help me figure out a way to get the angle. thank You

velocity and acceleration are vectors... can you write the two velocities in vector form... (use i and j vectors). Then calculate average acceleration just as you did, but you'll be subtracting two vectors...
 
  • #3
sorry i missed type what i did i did subtract i did a=9-(-18)/14 and i got 1.93. i know the answer is 1.37 but i don't know how to get it
 
  • #4
jperk980 said:
sorry i missed type what i did i did subtract i did a=9-(-18)/14 and i got 1.93. i know the answer is 1.37 but i don't know how to get it

You can't subtract like that because east and south aren't along the same line... write the two velocities as vectors (using i for east west... j for north south).

For example: 20m/s west is

[tex]\vec{v} = -20\vec{i}[/tex]

20m/s north is:
[tex]\vec{v} = 20\vec{j}[/tex]

Does this make sense?

If the notation doesn't make sense... then try it like this... what is the average acceleration in the east west direction (taking east as positive) ?

what is the average acceleration in the north south direction (taking north as positive) ?

What is the magnitude of the net acceleration?
 

Related to Average acceleration using vectors

What is average acceleration using vectors?

Average acceleration using vectors is a measure of the change in velocity over a certain period of time. It takes into account both the magnitude and direction of the change in velocity.

How is average acceleration using vectors calculated?

To calculate average acceleration using vectors, you need to take the difference between the final and initial velocities and divide it by the time taken for the change to occur. This can be represented using the equation a = (vf - vi) / t, where a is the average acceleration, vf is the final velocity, vi is the initial velocity, and t is the time taken.

What are the units for average acceleration using vectors?

The units for average acceleration using vectors are meters per second squared (m/s2). This represents the change in velocity over a certain period of time.

How is average acceleration using vectors different from average acceleration?

Average acceleration using vectors takes into account both the magnitude and direction of the change in velocity, while average acceleration only considers the magnitude. This means that average acceleration using vectors gives a more accurate representation of how an object's velocity changes over time.

What are some real-life examples of average acceleration using vectors?

Some real-life examples of average acceleration using vectors include a car accelerating on a curved road, a ball being thrown in the air, and a rocket launching into space. In all of these cases, the object's velocity is changing in both magnitude and direction, making average acceleration using vectors a useful measure.

Similar threads

Vectors, how to find average acceleration
    • Introductory Physics Homework Help
Replies
13
Views
6K
Average Speed Question for a Train that Accelerates and then Decelerates
    • Introductory Physics Homework Help
Replies
20
Views
1K
Question about the average acceleration
    • Introductory Physics Homework Help
Replies
16
Views
1K
Relating acceleration to distance and time
    • Introductory Physics Homework Help
Replies
5
Views
1K
Calculate Distance Traveled: Instantaneous vs. Average Velocity
    • Introductory Physics Homework Help
Replies
5
Views
1K
Direction and velocity vector problem
    • Introductory Physics Homework Help
Replies
2
Views
3K
A ball bounces off a brick wall, Find the average acceleration
    • Introductory Physics Homework Help
Replies
5
Views
4K
Angle of average acceleration while turning a curve
    • Introductory Physics Homework Help
Replies
8
Views
2K
What is the average acceleration vector given a car's north and east velocities?
    • Introductory Physics Homework Help
Replies
1
Views
2K
Find average acceleration - vectors
    • Introductory Physics Homework Help
Replies
19
Views
2K

Hot Threads

Recent Insights

Back
Top