Air pressure is usually highest when the air is
a.) cool and humid
b.) cool and dry
c.) warm and humid
d.)warm and dry

Find an expression for the electric field e⃗ at the center of the semicircle. hint: a small piece of arc length δs spans a small angle δθ=δs /r, where r is the radius. express your answer in terms of the variables q, l, unit vectors i^, j^, and appropriate constants.