QUESTION 3 6 points Save Answer 6 pointsSave Answer Three id

QUESTION 3 6 points Save Answer 6 pointsSave Answer Three identical particles of mass m-5.5 grams and charge qF-4.5 microCoulombs are assembled from infinity to form an equilateral triangle with sides of length d-8cm as shown in the figure. Three identical particles of mass m=5.5 grams and charge q=4.5 microCoulombs are assembled from infinity to form an equilateral triangle with sides of length d-8 cm as shown in the figure Let W be the work required to assemble the triangle of charges by the following method. Charge A is first nailed down. Charge B is then moved from infinity and nailed down at a distance d from Charge A. Finally Charge C is moved in from infinity and nailed down at the apex of the triangle What is the total work against the repulsive forces to assemble the triangle in units of Joules?

Solution

When charge were at very far distance apart then PE of system will be zero.

when come and form traingle then PE will be

PE = 3 [ k (4.5uC) (4.5uC) / (0.08^2) ]

PE = (3 x 9 x 10^9 x 4.5 x 10^-6 x 4.5 x 10^-6 ) / (0.08^2)

PE = 85.43 J

So work done W will be change in PE.

W =85.43J