Two fixed point charges at and at exert electrostatic forces on a third charge placed…

PHYSICS · Subjective · A Level · Physics · Fields and their consequences · Fields and their consequences

Problem

Two fixed point charges

q_1 = +3\,\mu\text{C}

P(2\,\text{cm},\,-1\,\text{cm})

and

q_2 = -4\,\mu\text{C}

Q(-3\,\text{cm},\,4\,\text{cm})

exert electrostatic forces on a third charge

q_3 = +2\,\mu\text{C}

placed at

R(1\,\text{cm},\,1\,\text{cm})

in vacuum. (a) Calculate the distance

PR

and the distance

QR

. (b) Determine the magnitudes of the individual forces acting on

q_3

due to

q_1

and

q_2

. (c) Resolve each force into

x

and

y

components, taking the usual Cartesian axes. (d) Find the algebraic sum of components to obtain the net

x

and

y

components of the force on

q_3

. (e) Compute the magnitude of the resultant force on

q_3

. Express the final answer correct to two significant figures.