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Physics 19 Homework 2: Electric Charges and Forces DUE: September 4, 2018 at 11:

ID: 1877047 • Letter: P

Question

Physics 19 Homework 2: Electric Charges and Forces DUE: September 4, 2018 at 11:59pm This assignment is to be turned in on Catcourses by 11.59pm on September 4, 2018. Late homework will not be accepted. You are encouraged to work with classmates, but the work you in must be your own. 1. Adenine and Thymine. In class, we found the attractive force between adenine and thymine due to the O - H-N combination. Now, determine the net force exerted between thymine and adenine. Assume that the O - H - N and the N - H - N combinations are parallel to each other so your cakculations will only be in one dimension. Note that the distance between the H-N is 0.11 nm and each + and - in the figure represents a unit charge of q 1.60x 10" C Thymine (T 280nm -0.280 nm- Adenine (A) -10 .300mm 3x10m 0.300 nm OHN 1.11 nm 2. 0H rorn OH HN

Explanation / Answer

For combination O-H-N,

net force = FON - FOH

F1 = ke^2 / r^2 - ke / r'^2

F1 = 9*109 * (1.6*10-19)^2 * [1 / (0.28*10-9)^2 - 1 / (0.0.28*10-9 - 0.11*10-9)^2]

F1 = -5.033*10-9 N

For combination N-H-N,

net force = FNN - FHN

F2 = ke^2 / r^2 - ke / r'^2

F2 = 9*109 * (1.6*10-19)^2 * [1 / (0.30*10-9)^2 - 1 / (0.0.30*10-9 - 0.11*10-9)^2]

F2 = -3.82*10-9 N

Attractive force b/w adenine and thymine,

F = F1 + F2

F =  -5.033*10-9 - 3.82*10-9

F = -8.85*10-9 N