HW8_Sol_F10

# HW8_Sol_F10 - Oct 18 2010 PHYS 2101 HW#8 WileyPlus Problem...

This preview shows pages 1–2. Sign up to view the full content.

Oct. 18, 2010 PHYS 2101 HW#8 WileyPlus Problem Solutions 1 HW #8 Solutions – or at least most of them… (USING BOOK VALUES 9 th Edition in problems; problem # indicated by []) 2) [13-6] The gravitational forces on m 5 from the two 5.00 g masses m 1 and m 4 cancel each other. Contributions to the net force on m 5 come from the remaining two masses: The force is directed along the diagonal between m 2 and m 3 , toward m 2 . In unit-vector notation, we have . 3) [13-9] Both the Sun and the Earth exert a gravitational pull on the space probe. The net force can be calculated by using superposition principle. At the point where the two forces balance, we have , where M e is the mass of Earth, M s is the mass of the Sun, m is the mass of the space probe, r 1 is the distance from the center of Earth to the probe, and r 2 is the distance from the center of the Sun to the probe. We substitute r 2 = d ! r 1 , where d is the distance from the center of Earth to the center of the Sun, to find Using the values for M e , M s , and d given in Appendix C, we take the positive square root of both sides to solve for r 1 . A little algebra yields Note: The fact that indicates that the probe is much closer to the Earth than the Sun. 4) [13-10] Using Eq. 13-1, we find F AB " = 2 Gm A 2 d 2 j ^ and F AC " = 4 Gm A 2 3 d 2 i ^ . Since the vector sum of all three forces must be zero, we find the third force (using magnitude-angle notation) is F AD " = Gm A 2 d 2 (2.404 # –56.3º) . This tells us immediately the direction of the vector r " (pointing from the origin to particle D ), but to find its magnitude we must solve (with m D = 4 m A ) the following equation: 2.404 \$ % & ' ( ) Gm A 2 d 2 = Gm A m D r 2 . This yields r = 1.29 d . In magnitude-angle notation, then, r " = (1.29 # –56.3º) , with SI units understood. The “exact” answer without regard to significant figure considerations is (a) In ( x, y ) notation, the x

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern