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Unformatted text preview: Muraj, Hamza – Final 1 – Due: May 10 2006, 11:00 pm – Inst: Florin 1 This printout should have 40 questions. Multiplechoice questions may continue on the next column or page – find all choices before answering. The due time is Central time. 001 (part 1 of 1) 10 points Newton’s law of gravity is given by: F = G m 1 m 2 r 2 . In terms of fundamental units, G has the unit of: (M: mass, L: length, T: time) 1. M 1 L 3 T 1 . 2. M 2 L 1 T 2 . 3. M 1 L 2 T 1 . 4. M 1 L 2 T 2 . 5. M 1 L 1 T 2 . 6. M 1 L 1 T 1 . 7. M 1 L 3 T 2 . correct 8. M 2 L 2 T 2 . Explanation: G = F r 2 m 1 m 2 = ⇒ [ G ] = • F r 2 m 1 m 2 ‚ = • mar 2 m 2 ‚ = M ( LT 2 ) L 2 M 2 = M 1 L 3 T 2 . 002 (part 1 of 3) 10 points Consider the plot below describing motion along a straight line with an initial position of x = 10 m. 2 1 1 2 3 4 5 1 2 3 4 5 6 7 8 9 time (s) velocity(m/s) What is the acceleration at 1 second? Correct answer: 2 . 5 m / s 2 . Explanation: Basic Concepts: The plot shows a curve of velocity versus time . The acceleration is the slope of the velocity curve µ a = dv dt = Δ v Δ t ¶ . The position is the area under the velocity curve µ x = x + Z v dt = x + v t + 1 2 at 2 ¶ . The area of a triangle is onehalf the base × the height. The area of a trapezoid is onehalf the height × the sum of the bases. Solution: The slope of the velocity curve from 0 seconds to 2 seconds is a = v f v i t f t i = (5 m / s) (0 m / s) (2 s) (0 s) = 2 . 5 m / s 2 . 003 (part 2 of 3) 10 points What is the velocity at 2 seconds? Correct answer: 5 m / s. Explanation: The velocity at 2 seconds can be read off the plot (5 m / s); however, it can also be calculated: v = v i + a ( t f t i ) = (0 m / s) + (2 . 5 m / s 2 )[(2 s) (0 s)] = 5 m / s . Muraj, Hamza – Final 1 – Due: May 10 2006, 11:00 pm – Inst: Florin 2 004 (part 3 of 3) 10 points What is the position at 2 seconds? Correct answer: 15 m. Explanation: The initial position given in the problem is 10 m. 1 2 3 4 5 6 7 8 9 1 2 3 4 5 1 2 time (s) velocity(m/s) The position at 2 seconds is 10 meters plus the area of the triangle (shown in gray in the above plot) x = (10 m) + 1 2 [(2 s) (0 s)] × [(5 m / s) (0 m / s)] = 15 m; however, it can also be calculated: x = x i + v i ( t f t i ) + 1 2 ( t f t i ) 2 = (10 m) + (0 m / s)[(2 s) (0 s)] + 1 2 (2 . 5 m / s 2 )[(2 s) (0 s)] 2 = 15 m . 005 (part 1 of 1) 10 points A bowling ball accidentally falls out of the cargo bay of an airliner as it flies along in a horizontal direction. Y X W U V Z As observed by a person standing on the ground and viewing the plane as in the fig ure, which path would the bowling ball most closely follow after leaving the airplane?...
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This note was uploaded on 04/12/2010 for the course PHY 58195 taught by Professor Turner during the Spring '09 term at University of Texas.
 Spring '09
 Turner

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