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Unformatted text preview: PHYSICS 2D WINTER 2010 FINAL EXAM SOLUTIONS 1 (a) Let us assume enemy spaceship (reference frame S ′ ) is approaching your ship (reference frame S) from left with velocity v = 0.4 c along x-axis. Velocity of missile in S ′ = u x ′ = 0.7c along x-axis. Use reverse velocity transformation to get speed u x in reference frame S. u x = ′ υ ξ + ω 1 + υ ξ ω / χ 2 = 0.7 χ + 0.4 χ 1 + (0.729 (0.429 = 1.1 1.28 χ = 0.86 χ (b) In reference frame S, missile was fired at distance L = 8 x 10 9 m and is approaching with speed of 0.86c so time taken in Reference frame S = (8 x 10 9 )/ (0.86 x 3 x 10 8 ) s = 31 secs = T, say. (c) In reference frame S ′ , because you are moving with velocity v relative to him, when he fired, your distance by his measurement was only 1- ω 2 χ 2 Λ from him, because of length contraction . If he estimates time T ′ for missile to reach you, you will have in his frame moved a distance vT ′ towards him, so ′ T = 1 - v 2 c 2 L- v ¢ T ¢ u x ¢ T (1 +...
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This note was uploaded on 04/02/2010 for the course PHYS 2D 2D taught by Professor Sinha during the Spring '10 term at UCSD.
- Spring '10