Calculating amount of revolutions

  • Thread starter smpolisetti
  • Start date
  • Tags
    Revolutions
In summary, the conversation discusses how to calculate the number of revolutions a high-speed drill makes in 0.260 seconds, given its initial and final angular velocity of 0 and 2760 rpm, respectively. The solution involves converting the rpm to radians per second and then multiplying by the time, resulting in 270,528.83 radians. This value is then converted to revolutions, giving a final answer of 43,056 revolutions.
  • #1
smpolisetti
10
0

Homework Statement


A high-speed drill reaches 2760 rpm in 0.260 s. Through how many revolutions does the drill turn during this first 0.260 s?
2. The attempt at a solution

UPDATED:

Here's what I have right now

2760 rpm * (2n/1 rev) * (60 s / 1 min) = 1040495.49 rad/s

1040495.49 rad/s * 0.260 s = 270,528.83 radians

270,528.83 radians * (1 rev / 2n) = 43,056 revolutions

Is that right? I haven't put the answer in because I have a limited amount of tries but I want to make sure I did it right.
 
Last edited:
Physics news on Phys.org
  • #2
smpolisetti said:
To calculate the amount of revolutions I divided rpm to convert it by seconds and then multiplied by 0.260 seconds but that's wrong.


when you converted rpm you got rad/s. So multiplying that by 0.26s will give you the radians it moved.

now you know that 2π rad = 1 rev.

You need to do another conversion to get the revolutions.
 
  • #3
I divided 11.96 by 2pi and got 1.90 revolutions, but the computer program says that's wrong. What's my mistake?
 
  • #4
You know the final (and initial) angular velocity and the time it took to get there. With this you can get the angular acceleration. Given that, you can find how many revolutions it traversed in the given time.
 
  • #5
Hi smpolisetti, welcome to PF.
in the problem. initial angular velocity is zero and final angular velocity = 2760*2π/60 rad./s.
Find the angular acceleration using ω = ωο + α*t.
Then find the angular displacement using θ = ωο*t + 1/2*α*t^2
 
  • #6
I know that the acceleration is 1110 rad/s/s but I don't know how to get the amount of revolutions from that
 
  • #7
smpolisetti said:
I know that the acceleration is 1110 rad/s/s but I don't know how to get the amount of revolutions from that

no no 2760 rpm you have.

1 rpm = 2π/60 rad/s

you do not need angular acceleration.

Convert the rpm to rad/s and then multiply by the 0.26 sec.
 
  • #8
Here's what I have

2760 rpm * (2n/1 rev) * (60 s / 1 min) = 1040495.49 rad/s

1040495.49 rad/s * 0.260 s = 270,528.83 radians

270,528.83 radians * (1 rev / 2n) = 43,056 revolutions

Is that right? I haven't put the answer in because I have a limited amount of tries but I want to make sure I did it right.
 
  • #9
Angular acceleration = 1100 rad/s/s.

θ = ωο*t + 1/2*α*t^2

θ = 1/2*1100*(0.26)^2

find θ and then find n.
 
  • #10
Thanks so much!
 

1. What is the formula for calculating amount of revolutions?

The formula for calculating the amount of revolutions is revolutions = distance / circumference, where distance is the total distance traveled and circumference is the distance around the circle.

2. How do you measure the distance and circumference for calculating revolutions?

The distance can be measured using a ruler or measuring tape, and the circumference can be measured using a string or flexible measuring tape by wrapping it around the circle and then laying it flat to measure the length.

3. Can the amount of revolutions be calculated for any circular motion?

Yes, the amount of revolutions can be calculated for any circular motion, as long as the distance and circumference are known.

4. How do you convert revolutions to another unit of measurement?

To convert revolutions to another unit of measurement, first determine the circumference of the circle in the desired unit of measurement. Then, multiply the number of revolutions by the circumference to get the distance traveled in the new unit of measurement.

5. How does the size of the circle affect the number of revolutions?

The size of the circle does not affect the number of revolutions. The amount of revolutions is determined by the distance traveled and the circumference, which remains constant regardless of the size of the circle.

Similar threads

  • Introductory Physics Homework Help
Replies
9
Views
299
  • Introductory Physics Homework Help
Replies
1
Views
3K
  • Introductory Physics Homework Help
Replies
13
Views
423
  • Introductory Physics Homework Help
Replies
4
Views
1K
  • Introductory Physics Homework Help
Replies
10
Views
1K
  • Introductory Physics Homework Help
Replies
2
Views
1K
  • Introductory Physics Homework Help
Replies
7
Views
2K
  • Introductory Physics Homework Help
Replies
18
Views
2K
  • Introductory Physics Homework Help
Replies
1
Views
1K
  • Introductory Physics Homework Help
Replies
3
Views
1K
Back
Top