39_new - Ch1-H1 florin (56950) This print-out should have...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Ch1-H1 – florin – (56950) 1 This print-out should have 30 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. 001 (part 1 of 7) 3.0 points A proton is located at: h4 × 10 10 m, −1 × 10 10 m, 9 × 10 10 mO . Find ~r, the location of the proton from the origin where ~r = hr x , r y , r z O. What is r x in meters? Your answer must be within ± 5.0% Correct answer: 4 × 10 10 m. Explanation: The position of the proton is the vector from the origin to the location of the proton. In this case: h4 × 10 10 m, −1 × 10 10 m, 9 × 10 10 mO 002 (part 2 of 7) 3.0 points What is r y in meters? Your answer must be within ± 5.0% Correct answer: −1 × 10 10 m. Explanation: The position of the proton is the vector from the origin to the location of the proton. In this case: h4 × 10 10 m, −1 × 10 10 m, 9 × 10 10 mO 003 (part 3 of 7) 3.0 points What is r z in meters? Your answer must be within ± 5.0% Correct answer: 9 × 10 10 m. Explanation: The position of the proton is the vector from the origin to the location of the proton. In this case: h4 × 10 10 m, −1 × 10 10 m, 9 × 10 10 mO 004 (part 4 of 7) 2.0 points What is |~r| in meters? Your answer must be within ± 5.0% Correct answer: 9.89949 × 10 10 m. Explanation: The magnitude of ~r is found by: q |~r| = r x 2 + r y 2 + r z 2 where: r x = 4 × 10 10 m r y = −1 × 10 10 m r z = 9 × 10 10 m therefore: |~r| = 9.89949 × 10 10 m 005 (part 5 of 7) 3.0 points What is ˆr x , the x component of the unit vector in the direction of ~r? Your answer must be within ± 5.0% Correct answer: 0.404061. Explanation: The unit vector has the form: ˆr = | ~r ~r| . This means that the x component of the unit vector is: ˆr x = r x |~r| 4 × 10 10 m = 9.89949 × 10 10 m = 0.404061 7 (part 6 of 7) 3.0 points What is ˆr y , the y component of the unit vector in the direction of ~r? Your answer must be within ± 5.0% Correct answer: −0.101015. Explanation: The unit vector has the form: ˆr = | ~r ~r| .
Background image of page 1

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

View Full DocumentRight Arrow Icon
Ch1-H1 – florin – (56950) 2 This means that the y component of the unit vector is: ˆr y = r y |~r| −1 × 10 10 m = 9.89949 × 10 10 m = −0.101015 8 (part 7 of 7) 3.0 points What is ˆr z , the z component of the unit vector in the direction of ~r? Your answer must be within ± 5.0% Correct answer: 0.909137. Explanation: The unit vector has the form: ˆr = | ~r ~r| . This means that the z component of the unit vector is: ˆr z = r z |~r| 9 × 10 10 m = 9.89949 × 10 10 m = 0.909137 9 (part 1 of 5) 10.0 points A planet is located at ~ 10 10 10 P = h−3 × 10 , 5 × 10 , −5 × 10 O. A star is located at ~ 10 10 10 S = h4 × 10 , −7 × 10 , 1 × 10 O. What is ~ , the vector pointing from the planet R to the star? ~ 10 11 10 1. R = h7 × 10 , −1.2 × 10 , 7 × 10 O ~ 10 11 10 2. R = h7 × 10 , −1.2 × 10 , 6 × 10 O correct ~ 10 11 10 3. R = h5 × 10 , −1.2 × 10 , 3 × 10 O ~ 10 11 10 4. R = h5 × 10 , −1.3 × 10 , 4 × 10 O 5. ~ = h9 × 10 −7 × 10 5 × 10 O R , , Explanation: This is a vector subtraction problem. To find ~ , we subtract ~ ~ by respective com- R S P ponents: S x − P x = 4 × 10 10 − (−3 × 10 10 ) = 7 × 10 10 S y − P y = −7 × 10 10 − (5 × 10 10 ) = −1.2 × 10 11 S z − P z = 1 × 10 10 − (−5 × 10 10 ) = 6 × 10 10 So
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/04/2012 for the course PHY 303K taught by Professor Turner during the Spring '08 term at University of Texas.

Page1 / 8

39_new - Ch1-H1 florin (56950) This print-out should have...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online