You are Here: Home >< Physics

# A2 physics question electric fields watch

1. http://pmt.physicsandmathstutor.com/...%20A-level.pdf

Question 4 (b) ii (and 4 b i, I'm confused as to why the electrostatic force acts left?)

And part b ii I just dont really understand how to approach..

Any help would be appreciated guys!

Cheers
2. (Original post by iMacJack)
http://pmt.physicsandmathstutor.com/...%20A-level.pdf

Question 4 (b) ii (and 4 b i, I'm confused as to why the electrostatic force acts left?)

And part b ii I just dont really understand how to approach..

Any help would be appreciated guys!

Cheers
You know it's in equilibrium. Tension acts along the string, whose horizontal component would want to displace the bob right, gravity wants to make it go to the right so the electric force must go to the left, otherwise how else would it be in equilibrium?

Then you just need to resolve along the direction perpendicular to the wire, using the force from the previous part and N2L - just in the way that you would approach a standard equilibrium question in M1.
3. (Original post by kingaaran)
You know it's in equilibrium. Tension acts along the string, whose horizontal component would want to displace the bob right, gravity wants to make it go to the right so the electric force must go to the left, otherwise how else would it be in equilibrium?

Then you just need to resolve along the direction perpendicular to the wire, using the force from the previous part and N2L - just in the way that you would approach a standard equilibrium question in M1.
Ahhh cheers that makes a lot more sense, I got like 15.4 degrees, the answer says around 15.2 but I assume 15.4 would be marked correct?

Thanks again
4. (Original post by iMacJack)
Ahhh cheers that makes a lot more sense, I got like 15.4 degrees, the answer says around 15.2 but I assume 15.4 would be marked correct?

Thanks again

### Related university courses

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: January 10, 2017
Today on TSR

### Exam Jam 2018

Join thousands of students this half term

### Solo - A Star Wars Story

Poll

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE