What are the physics problems involving velocity and acceleration?

In summary, the conversation discusses two physics problems, one involving finding average velocity and the other dealing with rate of acceleration, average velocity, and distance. The first problem is solved using the equation v=d/t, while the second problem is left for the person to solve on their own. The importance of including units in the answer is also emphasized.
  • #1
meteoguy04
Hi,

I'm having trouble with two physics problems.

- Ashley runs 3.0 km in 4.00 minutes. What is her average velocity? The answer is 45 but I can't figure out how to get it.

- A train moving at 15 km/hr takes 1 minute to come to a stop, find its rate of acceleration, its average velocity and the distance it takes to stop.

Rate of Acceleration
--------------------

15/60 = .25

Average Velocity
----------------

Need help finding this

Distance
--------

15/3.6 = 4.16

4.16 m/s
-------- = .069 m/s^2
60s

Thanks!
 
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  • #2
- Ashley runs 3.0 km in 4.00 minutes. What is her average velocity? The answer is 45 but I can't figure out how to get it.

Use the equation
v=d/t
v=3/4

- A train moving at 15 km/hr takes 1 minute to come to a stop, find its rate of acceleration, its average velocity and the distance it takes to stop.

To find your average velocity, use the same equation as I used above (do it yourself this time so you learn.)
 
  • #3
Thanks quantum!

I got 3/4 = .75 = .75*60 = 45 for the first one...

For the second one I got 15/60 = .25*60 = 15...

Thanks again!
 
  • #4
metioguy04: Let me suggest you do something that quantum also did not do: Write the units with the answer!

You asserted that the answer was 45.

Well, no, the answer CAN'T be 45. The answer has to be a speed and 45 is a number, not a speed. That might seem picky but had you written 45 km/HOUR it would have been a heckuvalot easier to see what to do. Since you gave the time in minutes, the natural thing to do is to answer in km/min.
 
  • #5
LOL! Looked right over that... Sorry.
 

What is her average velocity?

1. What is the definition of average velocity?
Average velocity is a measure of the overall displacement of an object over a period of time. It takes into account both the distance and direction of an object's movement.

2. How is average velocity calculated?
Average velocity is calculated by dividing the total displacement of an object by the total time it took to cover that distance. The formula is: average velocity = total displacement / total time.

3. What units are used to measure average velocity?
Average velocity is typically measured in units of distance per time, such as meters per second (m/s) or kilometers per hour (km/h).

4. How is average velocity different from instantaneous velocity?
Average velocity is an overall measure of an object's displacement over a period of time, while instantaneous velocity is the velocity of an object at a specific moment in time.

5. What factors can affect an object's average velocity?
An object's average velocity can be affected by changes in its speed, direction, or both. It can also be influenced by external forces such as friction or air resistance.

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