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Unformatted text preview: alexander (jra2623) – homework 08 – Turner – (92510) 1 This print-out should have 10 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. 001 (part 1 of 3) 10.0 points A ball is thrown and follows the parabolic path shown. Point Q is the highest point on the path and points P and R are the same height above the ground. Q R P How do the speeds of the ball at the three points compare? Air friction is negligible. 1. bardbl vectorv P bardbl < bardbl vectorv Q bardbl < bardbl vectorv R bardbl 2. bardbl vectorv P bardbl = bardbl vectorv R bardbl < bardbl vectorv Q bardbl 3. bardbl vectorv Q bardbl < bardbl vectorv R bardbl < bardbl vectorv P bardbl 4. bardbl vectorv Q bardbl < bardbl vectorv P bardbl = bardbl vectorv R bardbl correct 5. bardbl vectorv R bardbl < bardbl vectorv Q bardbl < bardbl vectorv P bardbl Explanation: The speed of the ball in the x-direction is constant. Because of gravitational accelera- tion, the speed in the y-direction is zero at point Q . Since points P and R are located at the same point above ground, by symmetry they have the same vertical speed component (though they do not have the same velocity), so v Q < v P = v R . 002 (part 2 of 3) 10.0 points Which diagram best indicates the direction of the acceleration, if any, on the ball at point R ? 1. 2. 3. 4. 5. 6. correct 7. The ball is in free fall and there is no acceleration at any point on its path. 8. 9. Explanation: Since air friction is negligible, the only ac- celeration on the ball after being thrown is that due to gravity, which acts straight down....
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This note was uploaded on 10/20/2011 for the course PHY 302K taught by Professor Kaplunovsky during the Summer '08 term at University of Texas.
- Summer '08