Final Exam Key

# Final Exam Key - PHYS 121 (FA08) Final Exam 100 pts maximum...

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Unformatted text preview: PHYS 121 (FA08) Final Exam 100 pts maximum NAME (print clearly): You can bring a 3x5 inch index card. Only non-programmable and non-graphing calculator is allowed. You must show all work, not just the answers. A correct answer alone will receive zero points. Q1. A physics student on Planet Exidor throws a ball, and it follows the parabolic trajectory shown below. The ball's position is shown at 1s intervals until t=3 s. At t=1 s, the ball's velocity is v = (2.01+ 2.0 })m / s . a) What is the ball's velocity (in unit vector form) at t=2 s? (1 pt)-> j\ 1/ I ~ lJ-=: J.oi; fII;5------------ b) What is the ball's velocity (in unit vector form) at t=3 s? (1 pt) ..) A f. ()I'f' IT::: (J,oi- ;;.oj ) )/5 y v = (2.01. + 2.0}) rn/s x c) What is the value of g on Planet Exidor? (4 pts) ,'( /11/. b' ;::- il /YJ / Vjlt::/5 =::l 15 / !:.Jt;)5 ! 5> ~f ~ S,u f C{.ct, _ Vir- OJ,' if_ Ct,,- ,- Os d) What is the ball's velocity (in unit vector form) at t=Os. (3 pts) e) What was the ball's launch angle? (3 pts) W I~. 4fW!s ,,,, ..J.,.'A () = -- ~ _ _ , (LAV _ I _-L. X---------....... Q2. Burglars are trying to haul an 8QO-kgsafe up a ramp to their getaway truck. The ramp is tilted at angle 8=30° and the rope is parallel to the ramp. The coefficients of friction between the safe and the ramp are J.ls = 0.60 and Pk = 0.40. a) Draw a proper free-body diagram of the safe in a coordinate system. (1 pt) ~hat tension of the rope is maintained after the motion starts, does the safe move with constant velocity or constant acceleratIon? Explain your reasoning. (2 pts) 1hR '1 motes. "uM C~ "I ~ fdpt( !P6t'p,r:s tMu,fCfl'd 7/n{t.He f<,;1diZf'd16tJis /rS5'/1," tk /J"W/1lfIFI'/ k4/J2.f'4/ITZ.-, tk lid r '7 1'('- t1X':~ tNl/l be Fdl\~-t. I ~/J .~te tAJ// be c:£, (m>ftiJY/ aapktzr/!'nL . Page 2 of8 Q3. Two blocks of unequal mass (mA < mB) are pushed along a frictionless track as shown....
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## This note was uploaded on 08/28/2011 for the course PHYS 121 taught by Professor Angerson during the Spring '07 term at UMBC.

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Final Exam Key - PHYS 121 (FA08) Final Exam 100 pts maximum...

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