# Homework Help: Need some help to answer Some questions

1. Feb 14, 2006

### iloveuok

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

2. Feb 14, 2006

### marlon

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: Feb 14, 2006