- #1
THA
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The question and detail:
I setup the problem using energy conservation: K_a + U_a = K_b + U_b:
K_a = total kinetic energy of the 3 charges when they're at rest
U_a = total potential energy of the 3 charges when they're at rest
K_b = total kinetic energy of the 3 charges when they're far apart
U_b = total potential energy of the 3 charges when they're far apart
K_a = 0 since the charges don't initially move
U_b = 0 when they're far away (when they're infinitely far away)
That leaves: U_a = K_b
where U_a = 3*(k*q_1*q_2)/r so
K_b = 3*(k*q_1*q_2)/r
and the answer I got was 3 * (8.9*10^9 * (1.6*10^-19)^2)/(8.50×10^-10) = 8.04*10^-19 which is incorrect.
Am I on the right track solving the problem? What am I overlooking?
Two protons and an alpha particle are held at rest at the corners of an equilateral triangle whose side length is 8.50×10^-10 m. The particles are released and move apart. What is their total energy when they are far apart? Use 1.60×10^-19 C for the magnitude of the charge on an electron.
I setup the problem using energy conservation: K_a + U_a = K_b + U_b:
K_a = total kinetic energy of the 3 charges when they're at rest
U_a = total potential energy of the 3 charges when they're at rest
K_b = total kinetic energy of the 3 charges when they're far apart
U_b = total potential energy of the 3 charges when they're far apart
K_a = 0 since the charges don't initially move
U_b = 0 when they're far away (when they're infinitely far away)
That leaves: U_a = K_b
where U_a = 3*(k*q_1*q_2)/r so
K_b = 3*(k*q_1*q_2)/r
and the answer I got was 3 * (8.9*10^9 * (1.6*10^-19)^2)/(8.50×10^-10) = 8.04*10^-19 which is incorrect.
Am I on the right track solving the problem? What am I overlooking?