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Unformatted text preview: zakaria (mmz255) – Homework 02 – Yao – (58180) 1 This print-out should have 26 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. 001 10.0 points An object is shot vertically upward into the air with a positive initial velocity. What correctly describes the velocity and acceleration of the object at its maximum elevation? Velocity Acceleration 1. positive negative 2. zero negative 3. positive positive 4. zero zero 5. negative negative 002 10.0 points What is correct for an object released from rest at a certain height? 1. The object falls 9.8 m during the first second of time. 2. During each second the object falls 9.8 m. 3. The acceleration of the object is propor- tional to its weight. 4. The average velocity during the first sec- ond of time is 4.9 m/s. 5. The acceleration changes by 9.8 m/s every second. 003 (part 1 of 2) 10.0 points A projectile is fired straight up at a speed of 10 m/s. Approximately how long does it take to reach its highest point? 1. 4 seconds. 2. 8 seconds. 3. Not enough information to estimate. 4. 2 seconds. 5. 1 second. 6. 0.5 second. 004 (part 2 of 2) 10.0 points Approximately how long after being fired does it take to return to its initial position? 1. 0.5 second. 2. 2 seconds. 3. 4 seconds. 4. Not enough information to estimate. 5. 8 seconds. 6. 1 second. 005 10.0 points A student drops a rock from a bridge to the water 10 m below. The acceleration of gravity is 9 . 8 m / s 2 . With what speed does the rock strike the water? Answer in units of m / s. 006 10.0 points The acceleration due to gravity on planet X is one fifth that on the surface of the earth. If it takes 3 . 3 s for an object to fall a certain distance from rest on earth, how long would it take to fall the same distance on planet X? Answer in units of s. 007 10.0 points A ball is thrown up from the ground (point O ). On its way up it passed a point B . The time it takes to reach B is t OB = 1 3 t OA . zakaria (mmz255) – Homework 02 – Yao – (58180) 2 t h A y t OB h B t OA b b b b b b b b b b b b b b b b b b b b b b b b v O B A Find the height OB = h B in terms of OA = h A ....
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This note was uploaded on 06/05/2011 for the course PHYS 303K taught by Professor Niu during the Spring '08 term at University of Texas at Austin.
- Spring '08