Question

A small metal sphere has a mass of 0.16 g and a charge of -23.0 nC . It is 10 cm directly above an identical sphere with the same charge. This lower sphere is fixed and cannot move.

a. What is the magnitude of the force between the spheres?
b. If the upper sphere is released, it will begin to fall. What is the magnitude of its initial acceleration?

Answer 1

Explanation:

A) we know that the magnitude of force

$F= \frac{kq_1q_2}{d^2}$

$F= \frac{9\times10^9\times23\times10^{-9}\times23\times10^{-9}}{0.1^2$

= 4.761×10^{-4} N

Also, net force = gravitational force - electrostatic force

B) F_net = F_g - F_e

m×a = m×g - 4.761×10^-4

a = g - 4.761×10^{-4}÷m

a= 9.8 - (4.761×10^{-4} /0.16×10^{-3})

a= 9.8 -2.975625

a= 6.82 m/s