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PHYS HELP Problem 8: In the figure, the point charges are located he corners of

ID: 1267908 • Letter: P

Question

PHYS HELP

Problem 8: In the figure, the point charges are located he corners of an equilateral triangle 25 cm on a side. qa Randomized Variables 25 cm Part (a Find the magnitude of the electric field in NC at the location of qa, given that qb 11.7 Hc and qc --4.1 uc Numeric A numeric value is expected and not an expression Part (b Find the direction of the electric field at qa in degrees above the ne with origin at ga. Numeric A numeric value is expected and not an expression Part (e) What is the magnitude of the force in N on qa, given that qa 1.2 nc? Numeric A numeric value is expected and not an expression Part (d) What is the direction of the force on qa in degrees above the ne ive x-axis with origin at ga? Numeric A numeric value is expected and not an expression.

Explanation / Answer

Part A)

Start with the formula for Electric Field...E = kq/r2

From qb...

E = (9 X 109)(11.7 X 10-6)/(.25)2

E = 1.68 X 106 N/C up and to the left

The x component is (1.68 X 106)(cos 60) = 8.42 X 105 N/C left

The y component is (1.68 X 106)(sin 60) = 1.46 X 106 N/C up

From qc...

E = (9 X 109)(4.1 X 10-6)/(.25)2

E = 5.90 X 105 N/C down and to the left

The x component is (5.90 X 105)(cos 60) = 2.95 X 105 N/C left

The y component is (5.90 X 105)(sin 60) = 5.11 X 105 N/C down

The net x = 8.42 X 105 + 2.95 X 105 = 1.14 X 106 N/C left

The net y = 1.46 X 106 - 5.11 X 105 = 9.49 X 105 N/C up

The net field is from the Pythagorean Theorem

net2 = (9.49 X 105)2 + (1.14 X 106)2

net = 1.48 X 106 N/C

Part B)

The direction is from the tangent formula

tan(angle) = 9.49 X 105/1.14 X 106

angle = 39.8o above the negative x axis

Part C)

F = qE

F = (1.2 X 10-9)(1.48 x 106)

F = 1.78 X 10-3 N

Part D)

The angle does not change from part B. It is still 39.8o above the negative x axis