Midterm1_Fall08_Key

# Midterm1_Fall08_Key - 1 An object moves along the x-axis...

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Unformatted text preview: 1. An object moves along the x-axis acCording to the equation: x(t) = (2 t3 — t + 5) m, where t is in seconds. Determine: (20 points) (a) the average speed between t = l s and t = 3 s (b) the instantaneous speed at t z 2 s (c) the average acceleration between t = l s and t = 3 3 (cl) the instantaneous acceleration at t = 2 s “1:31.262.qu +6 \J'LQ :aue _: 361— I Alt (QUQUS‘ '>((3j——)((U _[56~63m:m —w . ‘ 33 7 _ ‘ <3,ng its") 3 SH»%+‘S:SQ m 54(1) : Z-l'4'C—=LG (c) @Q : \JCB)~V(\3 ' ﬁgmjgn‘s‘m/S r “5 RH : Wm “‘zqmlfz 3-4 as "W “(3):: 6% %2— I “:3 53m]; WI) :2 64913.): inn/S 2. A truck is travelling with an initial constant speed of 14 m/s along a one-way street until the truck driver sees a car from a drunk driver travelling towards him in the same lane with a constant Speed of 10 m/s (contrary direction to the velocity of the truck). The truck driver immediately pushes his breaks and decelerates at a rate of -2.5 m/s2. The distance between the truck and the car when the truck driver ﬁrst saw the car was 90 m. Unfortunately, the truck driver could not avoid the collision. ( 7 points) (b) When will they collide? ( 7 points) (0) What will be the speed of the truck directly before the collision? (worms) Q :p-ZSW' Z \I‘ﬂY Lg VCO 2. , ThL‘le/‘g é“ "7L? ""4? W X (0-6 )(2 XItzclOm TRUCK _ {'2 “ X0 : VTO .{ QT CI» CM X2~x1 :VCW (z) (2) yz ; 9040i 4.298425% 90 2 ~ IE1 :g th ‘va— * if (b) x; ‘ sommﬂovggrmé : qum V \/ CC) H.— x?“ “r ‘ Q.‘ _ﬁ «‘6’ O :5 \{FT: (Erra‘é +_ %D:(~2‘sz( + Wm/f 3. A dog undergoes three consecutive displacements: Ar] = 5 m, 30° North of East Arg = 2 m, West [M3 = 7 m, 20° South of East Consider North to be the positive direction of the y—axis and East that of the x—axis. (21) Find the x and y components of the resultant displacement vector of the dog. (10 points) (b) Find the magnitude of the total displacement. (5 points) (c) In which direction will the dog need to walk in order to go back to its original position? (5 points) EN: :- A??? +7.13%: +57% ___ CH5 '1‘ X“ “‘1 w (5&5; 30°3+Sgﬂ3§®§1 AFB 3 — 2’3 m 3 b~> - I _ Q4 *7): I 3 V3 :(3c 3 '20 L bdngO’Slm Mil: Q‘Z’szﬁ tea/[85M ' on {ling—J? 8C: :5 @306" m" m (b) ‘8: El 4. A soccer player kicks a football from the ground from a point located 22 m (horizontally) away from the goal. The initial speed of the ball is 17 m/s and it is launched at an angle of 50° with respect to ground level. If the goal is 2.4 meters high and there is no goalkeeper: (Neglect air friction). (a) What will be the time of ﬂight of the ball from its launching position until it reaches the goal? (JOpoz'nrs) (b) Will the soccer player score a goal? What will be the height of the ball when it reaches the goal? (10 points) “3 we .: amt: oases 52=2mws<ftet4§ti a2) a 2 \QS‘in Sol: ~ (1’3 UL: @389“ A 2.9.0 Maggi 5. The two blocks in the diagram below are connected by a massless cord to a massless pulley. The masses of the blocks are: M1 2 3 kg, M2=7 Kg. The coefﬁcient of kinetic friction between M1 and the incline plane is 0.1. (a) Draw the force diagram. (2 points) (b) Obtain the acceleration of the system. (9 points) (c) Calculate the tension force on the cord. (9 points) CMVFNZBQ : N13 ~M\3 §;“'ZODM/L(p Miﬁ’ﬁ‘tﬂ 200 ...
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Midterm1_Fall08_Key - 1 An object moves along the x-axis...

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