This preview shows pages 1–3. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: hernandez (ejh742) oldhomework 08 Turner (58120) 1 This printout should have 14 questions. Multiplechoice questions may continue on the next column or page find all choices before answering. 001 (part 1 of 2) 10.0 points A cannon fires a 0 . 3 kg shell with initial ve locity v i = 8 . 7 m / s in the direction = 55 above the horizontal. x h 8 . 7 m / s 5 5 y y The shells trajectory curves downward be cause of gravity, so at the time t = 0 . 607 s the shell is below the straight line by some verti cal distance h . Your task is to calculate the distance h in the absence of air resistance. On what does h depend (besides g )? 1. It depends on some data not given in the problem. 2. It depends only on the initial angle , and does not depend on the flight time t or the initial velocity v i . 3. It depends on everything: the flight time t , the initial angle , and the initial velocity v i . 4. It depends on the initial angle and the initial velocity v i , but does not depend on the flight time t . 5. It depends on the flight time t and the initial angle , but does not depend on the initial velocity v i . 6. It depends only on the initial velocity v i , and does not depend on the flight time t or the initial angle . 7. It depends only on the flight time t , and does not depend on the initial velocity v i or the initial angle . correct 8. It depends on the flight time t and the initial velocity v i , but does not depend on the initial angle . 9. It is a constant and does not depend on the flight time t or the initial velocity v i or the initial angle . Explanation: In the absence of gravity, the shell would fly along the straight line at constant velocity: x = t v i cos , y = t v i sin . The gravity does not affect the x coordinate of the shell, but it does pull its y coordinate at constant downward acceleration a y = g , hence x = t v i cos , y = t v i sin  g t 2 2 . Thus, x = x but y = y 1 2 gt 2 , or in other words, the shell deviates from the straightline path by the vertical distance h = y y = g t 2 2 . Note that this result is completely indepen dent on the initial velocity v i or angle of the shell. It is a simple function of the flight time t and nothing else (besides the constant g = 9 . 8 m / s 2 ). 002 (part 2 of 2) 10.0 points Find the h . The acceleration of gravity is 9 . 8 m / s 2 . Correct answer: 1 . 8054 m. hernandez (ejh742) oldhomework 08 Turner (58120) 2 Explanation: h = g t 2 2 = (9 . 8 m / s 2 ) (0 . 607 s) 2 2 = 1 . 8054 m . 003 10.0 points For the ballistic missile aimed to achieve the maximum range of 14500 km, what is the maximum altitude reached in the trajectory?...
View
Full
Document
This note was uploaded on 06/14/2011 for the course PHY 303K taught by Professor Turner during the Spring '08 term at University of Texas at Austin.
 Spring '08
 Turner
 Physics, Work

Click to edit the document details