Question

A honey bee of mass 130 mg has accumulated a static charge of +1.5 pC. The bee is returning to her hive by following the path shown in the figure. Because Earth has a naturally occurring electric field near ground level of around 100 V/m pointing vertically downward, the bee experiences an electric force as she flies. What is the change in the bee’s electric potential energy, Δ?electric, as she flies from point A (0 m,0.4 m) to point B (5.3 m,3.9 m) ?

Answer 1

(a)

the equation for change in the bee’s electric potential energy, ΔU is

ΔU_E= qdel V= q Ed

= qE ( y2- y1)

=1.5* 10^-12 C(100 V/m) (3.9 m -0.4 m)

=5.25 * 10^-10 J

ΔU_g = mg (y2- y1) = 130* 10^-6 (9.8) (3.9 m-0.4 m) = 4.459* 10^-3 J

(b)

Δ?electric/Δ?grav = 5.25 * 10^-10 J/4.459* 10^-3 J = 1.17 * 10^-7