Why Are Dipole Forces Not Collinear in a Uniform Electric Field?

[Masafi]

I have attached the question, and the answer. I don't understand the answer given.

 

[berkeman]

I have attached the question, and the answer. I don't understand the answer given.

I agree that the answer is a bit obtuse, but do you understand how there is a torque on an electric dipole in an E-field? You can draw the F=qE force vectors if that helps...

 

[Masafi]

I agree that the answer is a bit obtuse, but do you understand how there is a torque on an electric dipole in an E-field? You can draw the F=qE force vectors if that helps...

It is an uniform electric field, but the forces are not collinear... Why is this?

 

[berkeman]

It is an uniform electric field, but the forces are not collinear... Why is this?

The forces are parallel when the dipole is sideways to the field, and colinear after the dipole aligns with the field. Can you draw the forces on a dipole, and describe what those forces will do to the dipole?