Need some help to answer Some questions

  • Thread starter iloveuok
  • Start date
In summary, The conversation is about someone who is having trouble answering questions related to circular motion and the Earth's angular speed. They are seeking help and have received a hint to use a formula relating orbital velocity to acceleration.
  • #1
iloveuok
2
0
Hi Guys,

I face some problems answering below questions. Anyone can help to answer?

Q1: One end of a string of length 1.0m is tied to body of mass 0.5kg. It is whirled in a vertical circle. If its angular speed is 3rev/s, calculate the tension in the string at the highest and lowest points.

Q2: (a) Calculate the angular speed of the earth.
(b) Calculate the
(i) Energy
(ii) Torque and (iii) average power
required to accelerate the Earth in 1 day from rest to its present angular speed.
(Mass of the Earth : 6x10 power 24 kg , radius of erath = 6400km)

Thanks.

Regards,
Alex
 
Physics news on Phys.org
  • #2
We cannot just give you the answers, that's against the PF Guidelines. Please show us what you have done so far.

regards
marlon

ps : as a hint to Q1. Can you link the orbital velocity to an acceleration (centripetal) ? There is a nice and easy formula for this. If you do this, you are on your way...
 
Last edited:
  • #3


Hello Alex,

I'd be happy to help you answer these questions. For Q1, we can use the equation T=mv^2/r to calculate the tension in the string at the highest and lowest points. At the highest point, the tension will be equal to the weight of the body, which is 4.9N. At the lowest point, the tension will be equal to the sum of the weight and the centripetal force, which is 9.8N.

For Q2, (a) the angular speed of the Earth can be calculated using the equation w=2π/T, where T is the period of one day. This gives us an angular speed of 7.27x10^-5 rad/s.

(b) (i) The energy required to accelerate the Earth can be calculated using the equation E=1/2Iw^2, where I is the moment of inertia of the Earth. This gives us an energy of 2.65x10^29 J.

(ii) The torque required can be calculated using the equation τ=Iα, where α is the angular acceleration of the Earth. This gives us a torque of 9.81x10^22 Nm.

(iii) The average power required can be calculated using the equation P=τw, where τ is the torque and w is the angular speed. This gives us an average power of 7.14x10^17 W.

I hope this helps answer your questions. Let me know if you need any further clarification. Good luck with your studies!

Best,
 

1. How do you define "help" in the context of answering questions?

"Help" in this context typically refers to providing information, guidance, or resources to assist in finding an answer to a question or problem.

2. What is the best approach to answering questions effectively?

The best approach is to actively listen to the question, research and gather relevant information, and provide a clear and concise response that is supported by evidence or logic.

3. How do you handle difficult or complex questions?

When faced with a difficult or complex question, it is important to break it down into smaller parts and address each part individually. It can also be helpful to collaborate with others or consult additional resources for a more comprehensive answer.

4. How can I improve my ability to answer questions accurately?

To improve your ability to answer questions accurately, it is important to continuously expand your knowledge and stay updated on relevant information in your field. Practicing active listening, critical thinking, and effective research skills can also improve your accuracy in answering questions.

5. Is it okay to ask for help when answering questions?

Yes, it is perfectly acceptable to ask for help when answering questions. In fact, consulting with others and seeking additional perspectives can lead to a more thorough and accurate response.

Similar threads

  • Introductory Physics Homework Help
Replies
4
Views
854
  • Introductory Physics Homework Help
Replies
10
Views
2K
  • Introductory Physics Homework Help
Replies
11
Views
2K
Replies
86
Views
4K
  • Introductory Physics Homework Help
Replies
2
Views
1K
  • Introductory Physics Homework Help
Replies
3
Views
2K
  • Introductory Physics Homework Help
Replies
8
Views
27K
  • Special and General Relativity
3
Replies
75
Views
3K
  • Introductory Physics Homework Help
Replies
2
Views
2K
  • Introductory Physics Homework Help
Replies
4
Views
2K
Back
Top