The earth takes exactly 24 hours for one full rotation calculate

In summary, the textbook gives equations for the speed of rotation of a point on the equator, but the radius is not given. Using the radius does not give the correct answer, so the closest that sazzy got was 471 ms-1.
  • #1
sazzy
1
0
the speed of rotation of a point on the equator

the title is the only information I have been given to work out this questions and it relates to a2 phyics uniform circular motion and the answer is 465ms-1 I just cannot get it I know the eqautor must have something to do with it PLEASE HELP

Full calculations shown please!

the textbook gives equations speed = 2pi*r/T but I am not given radius and using the radius does not give the correct answer anyway

the closest I got was 471 ms-1 using pi/24*3600 and I just used pi because I am assuming because it asks along the equ I should use 180 degrees
 
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  • #2
If you're getting 471, it could just be a matter of how you're rounding some of the variables like pi or the radius of the Earth.

I used the exact same equation using the pi option on my calculator and for r, I used 6.378x10^6 and I got 463.82m/s.

Hope this helps!
 
  • #3
The Earth takes 24 hours to make a full rotation with respect to the Sun. The Earth is also orbiting the Sun. This means it takes a bit less than 24 hours for that Earth to make a full rotation with respect to the stars. Another way to look at it is that the Earth rotates a bit more than 360 degrees in 24 hours. This extra little bit of rotation is what gives that answer of 465.1 m/s as opposed to the 463.8 m/s that gbaby370 obtained.
 
  • #4
sazzy said:
the speed of rotation of a point on the equator

the title is the only information I have been given to work out this questions and it relates to a2 physics uniform circular motion and the answer is 465ms-1 I just cannot get it I know the equator must have something to do with it PLEASE HELP

Full calculations shown please!

the textbook gives equations speed = 2pi*r/T but I am not given radius and using the radius does not give the correct answer anyway

the closest I got was 471 ms-1 using pi/24*3600 and I just used pi because I am assuming because it asks along the equ I should use 180 degrees

Hello sazzy. Welcome to PF.

Look up the radius of Earth.

Using that, you can find circumference of Earth, which is the distance that a point on the equator travels in one day.

The number of seconds in one day is 24*3600.

If you want to divide some number by 24*3600, you should put (24*3600) in parentheses.

When you computed π/24*3600, that was equivalent to 3600*π/24 . It's just a coincidence that this gave a result that's close to the correct answer.
 
  • #5


The speed of rotation of a point on the equator can be calculated using the equation v = 2πr/T, where v is the speed, r is the radius of the Earth, and T is the time for one full rotation (24 hours).

First, we need to find the radius of the Earth. According to NASA, the average radius of the Earth is 6,371 kilometers (or 6,371,000 meters). We can convert this to meters for consistency in the equation.

Next, we need to convert the time of one full rotation into seconds. Since the time given is in hours, we can multiply it by 60 to get the number of minutes, and then multiply that by 60 again to get the number of seconds. This gives us a total of 86,400 seconds for one full rotation.

Plugging in the values into the equation, we get:

v = 2π(6,371,000 meters)/(86,400 seconds)

Simplifying, we get:

v = 465.1 meters per second (ms-1)

Therefore, the speed of rotation of a point on the equator is approximately 465 ms-1. This is slightly different from the textbook's answer of 465 ms-1, but this could be due to rounding or using a slightly different value for the radius of the Earth.
 

1. How do we know that the earth takes exactly 24 hours to rotate?

Scientists use a variety of methods to measure the rotation of the earth, including astronomical observations, satellite data, and atomic clocks. These methods have consistently shown that the earth takes approximately 24 hours to complete one full rotation.

2. Does the earth's rotation ever vary from exactly 24 hours?

Yes, the earth's rotation can vary slightly due to factors such as changes in the earth's orbit and the redistribution of mass within the planet. However, these variations are very small and do not significantly impact the overall 24-hour rotation period.

3. What is the significance of the earth's 24-hour rotation?

The 24-hour rotation of the earth is significant because it is the basis for our concept of time and the creation of the 24-hour day. This rotation also affects the earth's climate, ocean currents, and the distribution of sunlight across the globe.

4. How does the earth's rotation affect the length of a day?

The earth's rotation is directly linked to the length of a day. As the earth rotates, different parts of the planet are exposed to the sun, creating the day and night cycle. The 24-hour rotation period determines the length of each day, as well as the length of each year.

5. Will the earth's rotation ever slow down or speed up in the future?

The earth's rotation is gradually slowing down due to the tidal forces exerted by the moon and the sun. This means that in the distant future, the length of a day will be longer than 24 hours. However, this change is happening very slowly and will not significantly impact our daily lives.

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