Richard Hallstein PHY231C Spring 2011 In Practice exam 2 1 hallstei msu Hallstein Richard Keep this exam CLOSED until advised by the instructor Fill out the bubble sheet last name rst initial and student number 60 minute long closed book exam A two sided 8 5 by 11 handwritten help sheet is allowed When done hand in your bubble sheet and your exam Possibly useful constants g 9 81 m s2 G 6 67 10 11 Nm2 kg2 5 67 10 8 W m2K4 R 0 0821 L atm mol K 8 31 J mol K Possibly useful Moments of Inertia Solid homogeneous sphere ICM 2 5 MR2 Thin spherical shell ICM 2 3 MR2 Thin uniform rod axis perpendicular to length ICM 1 12 ML2 Solid homogeneous cylinder axis through center of mass and parallel to length ICM 1 2 MR2 Useful information for Geometry Volume of a sphere V 4 3 r3 Volume of a cylinder V r2h Richard Hallstein PHY231C Spring 2011 In Practice exam 2 3 3 pt During a reworks show a skyrocket is launched much to the disappointment of the spectators the skyrocket mal functions breaking into two pieces at the top of its path and fails to give the much anticipated light show However one of the pieces is observed to move directly upward with velocity V1 The skyrocket s trajectory prior to the malfunction and the rst piece s velocity immediately after the malfunction are shown in the diagram below 8 pt Select the choice that most accurately depicts the velocity vector of the second piece immediately after the malfunction A B C D E F G H Immediately after the malfunction the direction of the sec ond piece s velocity is 1 C cid 13 D cid 13 E cid 13 F cid 13 A cid 13 G cid 13 B cid 13 H cid 13 The mass m1 enters from the left with velocity v0 and strikes a mass m2 m1 which is initially at rest The collision between the blocks is perfectly elastic The mass m2 then compresses the spring an amount x Immediately after the collision the energy of m2 is the initial energy of m1 2 A cid 13 True C cid 13 greater than B cid 13 False D cid 13 equal to E cid 13 less than Immediately after colliding with m2 the mass m1 stops and has zero velocity 3 A cid 13 True C cid 13 greater than B cid 13 False D cid 13 equal to E cid 13 less than Immediately after the collision the momentum of m2 is the initial momentum of m1 4 A cid 13 True C cid 13 greater than B cid 13 False D cid 13 equal to E cid 13 less than The maximum energy stored in the spring is the initial energy of m1 5 A cid 13 True C cid 13 greater than B cid 13 False D cid 13 equal to E cid 13 less than A 12 g bullet is red horizontally into a 70 g wooden block that is initially at rest on a frictionless horizontal surface and connected to a spring having spring constant 191 N m The bullet becomes embedded in the block The bullet block system compresses the spring by a maximum amount 85 cm 3 pt What was the initial velocity of the bullet in m s 7 A cid 13 119 2 E cid 13 372 8 C cid 13 210 8 G cid 13 659 5 B cid 13 158 5 F cid 13 495 9 D cid 13 280 3 H cid 13 877 1 Richard Hallstein PHY231C Spring 2011 In Practice exam 2 5 3 pt As shown in the gure a bullet of mass m 6 g and speed v passes completely through a pendulum bob of mass M 144 g The bullet emerges with a speed of v 2 The pendulum bob is suspended by a sti rod of length l 42 cm and negligible mass What is the minimum value of v such that the pendulum bob will barely swing through a complete vertical circle in m s 6 A cid 13 135 1 E cid 13 220 2 C cid 13 172 4 G cid 13 281 2 B cid 13 152 6 F cid 13 248 8 D cid 13 194 9 H cid 13 317 7 Richard Hallstein PHY231C Spring 2011 In Practice exam 2 7 A small object with a mass of m 837 g is whirled at the end of a rope in a vertical circle with a radius of r 132 cm 6 pt Identify the statements as being either True or False r m v 3 pt When it is at the location shown mid height its speed is v 4 34 m s Determine the tension in the rope in N 8 A cid 13 7 33 B cid 13 8 28 E cid 13 1 19 101 D cid 13 1 06 101 G cid 13 1 53 101 H cid 13 1 72 101 C cid 13 9 35 F cid 13 1 35 101 3 pt Calculate the magnitude of the total force acting on the mass at that location in N 9 A cid 13 1 00 101 B cid 13 1 14 101 C cid 13 1 28 101 F cid 13 1 85 101 D cid 13 1 45 101 E cid 13 1 64 101 G cid 13 2 09 101 H cid 13 2 36 101 Consider two planets orbiting a star If one planet has eight times the period of another it must also have four times the average orbital distance 10 A cid 13 True B cid 13 False If two planets have the same mass but the second has twice the gravity the second planet must also have one fourth the radius 11 A cid 13 True B cid 13 False An object moving in a circle with constant speed is accel erating 12 A cid 13 True B cid 13 False 3 pt A section of a high speed test track is circular with a radius of curvature R 1340 m At what angle of should the track be inclined so that a car traveling at 63 0 m s 141 mph would keep moving in a circle if there is oil on that section of the track i e it would not slip sideways even with zero friction on that section Hint The car s vertical acceleration is zero in deg 13 A cid 13 1 16 101 B cid 13 1 32 101 C cid 13 1 49 101 F cid 13 2 15 101 D cid 13 1 68 101 E cid 13 1 90 101 G cid 13 2 42 101 H cid 13 2 74 101 Richard Hallstein PHY231C Spring 2011 In Practice exam 2 9 6 pt A uniform frictionless pulley is attached to the ceiling in a gravity eld of 9 81 m s2 The mass of the pulley is Mp 3 pt A cylinder of radius R 0 300 m pivots …
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