Eb5 Calculate the average speed in km/h

In summary, the average speed of a person jogging eight complete laps around a 400m track in a total time of 14.5 min is approximately 13.2 km/h. The average velocity in this scenario is 0 because the person is running in a circular motion, constantly changing direction and not moving in a straight line. This is different from speed, which only measures the rate of motion and does not take direction into account.
  • #1
karush
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$\text{A person jogs eight complete laps around a $400 \, m$ track in a total time of $14.5 \, min$}. \\$
$\textit{a. Calculate the average speed in $km/h$}\\$
\begin{align*}\displaystyle \frac{(8)400 \, m}{14.5 \, min} \left(\frac{km}{1000m} \right) \left(\frac{60 \, min}{h} \right)&=\frac{192 \ km}{14.5 \, h}\\ &\approx\color{red}{13.2 \, km/h}\end{align*}

left out some steps but hope answer is correct
next question is average velocity
 
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  • #2
karush said:
$\text{A person jogs eight complete laps around a $400 \, m$ track in a total time of $14.5 \, min$}. \\$
$\textit{a. Calculate the average speed in $km/h$}\\$
\begin{align*}\displaystyle \frac{(8)400 \, m}{14.5 \, min} \left(\frac{km}{1000m} \right) \left(\frac{60 \, min}{h} \right)&=\frac{192 \ km}{14.5 \, h}\\ &\approx\color{red}{13.2 \, km/h}\end{align*}

left out some steps but hope answer is correct
next question is average velocity
Yes, that is correct. The average velocity is 0! Do you see why? What is the distinction between "speed" and "velocity"?
 
  • #3
well i thot $\textsf{average velocity, straight-line motion was}$\begin{align*}\displaystyle v_{av}&=\frac{x_2-x_1}{t_2-t_1}=\frac{\Delta x}{\Delta t}\end{align*}so we plug in what?
 
  • #4

But this is NOT "straight line motion"! Again, what is the difference between "speed" and "velocity"?
 
  • #6
HallsofIvy said:

But this is NOT "straight line motion"! Again, what is the difference between "speed" and "velocity"?

but isn't the ball being thrown strsight up and then fall straight down
 
  • #7
  • #8
karush said:
but isn't the ball being thrown strsight up and then fall straight down
Uh, no this is about a person running about an oval track! You seem to have two threads confused.
 
  • #9
Ok
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FAQ: Eb5 Calculate the average speed in km/h

1. What is the formula for calculating average speed in km/h?

The formula for calculating average speed in km/h is distance traveled divided by time taken. This can be represented as: Speed (km/h) = Distance (km) / Time (h).

2. How do I convert the units for distance and time to use the formula?

To use the formula for average speed in km/h, you will need to ensure that both distance and time are in the same units. For example, if distance is given in meters and time is given in minutes, you will need to convert meters to kilometers and minutes to hours before plugging them into the formula.

3. What if my distance and time values are not whole numbers?

The formula for average speed in km/h can still be used if the distance and time values are not whole numbers. Just make sure to use the exact values given, without rounding, to get the most accurate result.

4. Is average speed the same as instantaneous speed?

No, average speed and instantaneous speed are not the same. Average speed is the overall speed over a given distance and time, while instantaneous speed is the speed at a specific moment in time.

5. Can the formula for average speed in km/h be used for any type of motion?

Yes, the formula for average speed in km/h can be used for any type of motion, as long as the distance and time values are known. This includes both uniform motion (constant speed) and non-uniform motion (changing speed).

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