Two charges of $-1 C$ and $-3 C$ are positioned on a line at points $-2$ and $-4$ , respectively. What is the net force on a charge of $-3 C$ at $1$ ?

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Answer 1 · 2015-12-30T17:14:46

$0.8k$ units

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The resultant force will be the vector sum of the forces due to the other two particles.

$stackrel(rarr)(F_("res"))=stackrel(rarr)(F_(31))+stackrel(rarr)(F_(32)$

$stackrel(rarr)(F_(31))=k.(3xx3)/(5^2)=(k.9)/25$

$stackrel(rarr)(F_(32))=k.(2xx2)/(3^2)=(k.4)/9$

$:.stackrel(rarr)(F_("res"))=(k.9)/25+(k.4)/9$

$stackrel(rarr)(F_("res"))=k0.8$

If the units of length were in metres then $k=9xx10^(9)"m/F"$ and the result would be in Newtons.

The +ve sign means the force acts in the +ve direction i.e left to right.

Two charges of -1 C -1 C and -3 C -3 C are positioned on a line at points -2 -2 and -4 -4 , respectively. What is the net force on a charge of -3 C -3 C at 1 1 ?