TP 19.14

Given:

q₁ = +12.0 x 10^-6 C

q₂ = -24.0 x 10^-6 C

q₃ = +36.0 x 10^-6 C

d = 0.160 m

Find: F₁ -?

Force charge 2 exerts on charge 1:

F₂₁ = k |q₁||q₂|/d²

F₂₁ = (8.99 x 10⁹ N-m²/C²) |+12.0 x 10^-6 C||-24.0 x 10^-6 C|/(0.160)²

F₂₁ = 101 N to the right

Force charge 3 exerts on charge 1:

F₃₁ = k |q₁||q₃|/(2d)²

F₃₁ = (8.99 x 10⁹ N-m²/C²) |+12.0 x 10^-6 C||36.0 x 10^-6 C|/(0.320)²

F₃₁ = 37.9 N to the left

By superposition principle, the net force exerted on charge 1 is:

F₁ = F₂₁ + F₃₁= 101 N - 37.9 N = 63.1 N to the right