{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Quiz 1-solutions

# Quiz 1-solutions - Version 076 Quiz 1 Coker(56625 This...

This preview shows pages 1–4. Sign up to view the full content.

Version 076 – Quiz 1 – Coker – (56625) 1 This print-out should have 21 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. This is the first and easiest quiz, covering only the material in 3 chapters, Chs. 2, 3 and 4. 001 10.0 points A particle moves in a straight line with veloc- ity v ( t ) = 3 t 2 6 t . If it initially starts moving from 0 (where x = 0), then its position x ( t ) is equal to 1. x ( t ) = t 3 3 t 2 correct 2. x ( t ) = 6 t 6 3. x ( t ) = 6 t 4. x ( t ) = t 3 3 t 2 + 1 5. x ( t ) = 6 t 3 t 2 Explanation: v ( t ) = 3 t 2 6 t d s ( t ) dt = 3 t 2 6 t integraldisplay d s ( t ) dt dt = integraldisplay ( 3 t 2 6 t ) dt s ( t ) = t 3 3 t 2 + C x (0) = 0, so 0 = C and s ( t ) = t 3 3 t 2 . 002 10.0 points Consider the vector −→ M = (+ b, + c ) = + b ˆ ı + c ˆ  . d b a c c a b d d b a c c a b d D H B G C A E F x y Which vector is a valid representation of −→ M ? 1. E only. 2. C and G , but no others. 3. E and H , but no others. 4. F only. 5. G only. 6. F , C , D , and G , but no others. 7. E , A , H , and B , but no others. 8. A and B , but no others. correct 9. F and D , but no others. 10. B only. Explanation: Vectors A and B , but no others, have an x -displacement of + b and y -displacement of + c . The vector −→ M plotted with its tail at the origin is

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

View Full Document
Version 076 – Quiz 1 – Coker – (56625) 2 d b a c c a b d d b a c c a b d M x y Its length and direction are the same as vectors A and B , but no others. 003 10.0 points Vector vector A has a magnitude of 8 and points in the positive x -direction. Vector vector B has a magnitude of 21 and makes an angle of 27 with the positive x -axis. What is the magnitude of vector A vector B ? 1. 16.0801 2. 17.6379 3. 9.86934 4. 17.0749 5. 9.68872 6. 9.45618 7. 13.5208 8. 14.3395 9. 11.4659 10. 13.8608 Correct answer: 14 . 3395. Explanation: A A B B A B A B θ θ The component of vector vector B along the x -axis is B x = B cos θ = 21 cos 27 = 18 . 7111 and the component along the y -axis is B y = B sin θ = 21 sin 27 = 9 . 5338 . Vector vector A points in the x -direction, so it has no component along y -axis, so ( vector A vector B ) x = A x B x = 8 18 . 7111 = 10 . 7111 , ( vector A vector B ) y = A y B y = 0 9 . 5338 = 9 . 5338 , and bardbl vector A vector B bardbl = radicalBig ( 10 . 7111) 2 + ( 9 . 5338) 2 = 14 . 3395 . 004 10.0 points A target lies flat on the ground 9 m from the side of a building that is 10 m tall, as shown below. The acceleration of gravity is 10 m / s 2 . Air resistance is negligible. A student rolls a 9 kg ball off the horizontal roof of the building in the direction of the target. 9 m 10 m v 10 m The horizontal speed v with which the ball must leave the roof if it is to strike the target is most nearly 1. v = 9 m/s. 2. v = 3 9 m/s.
Version 076 – Quiz 1 – Coker – (56625) 3 3. v = 9 2 2 m/s. correct 4. v = 9 3 m/s. 5. v = 5 9 m/s. 6. v = 2 9 m/s.

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 ]}