Physics 140 Winter 2015 First Midterm Exam February 5 2015 Form 1 MIKE Yourname Last First SOLUTIOAJ 5 Your UMID number Fill in your name student ID number and form number on the scantron and in the spaces above All cell phones text massaging devices computers and communication devices of any type must be turned off and stowed out of sight The exam is closed book You may use one 3 x 5 7 5 cm x 12 5 cm notecard both sides You may also use a calculator that cannot communicate with the outside world You cannot share calculators notecards scratch paper exam booklets or scantrons Exam responses must be based on your individual work only You must mark the correct answer on the scantron to get credit for each problem The exam is 90 minutes long There are 20 multiple choice questions All questions are of equal value There is no penalty for guessing At the end of the exam hand in your scantron and show your UM ID Constants and equations you may find useful 2 g 9 8m1s 0 v x x t at 2 0 vo at v 2 2a x x 0 0 dv dt R 2 arad v Vp jB VB C W mg Fk J1kN j t C 0 cj 0 ID e l Cc 00 1 C 0 ID o Q ID 0c e c o I cQ II L C 1 I c I cJ 1 I cj 2 Circular freeway entrance and exit ramps are commonly banked to handle cars moving at 30 mph even in icy frictionless conditions To employ a similarly banked ramp for 60 mph traffic one would need to a increase the radius by a factor of b decrease the radius by a factor of c increase the radius by a factor of 2 increase the radius by a factor of 4 e increase the radius by a factor of 8 iv fAAj 17tS Sc J 44 J 4 a c 1 t V as t o tL t e 4I k 6 7 uj 4 e MA r a 3 A child plays with a toy train set with a track roughly of the oval shape shown The train moves clockwise at a constant speed all the way around the track At point P which arrow best represents the instantaneous acceleration vector of the train a Towards the center of the track b Tangent to the track c Perpendicular to the track outwards Perpendicular to the track inwards e None of the above j5 CueJ 71 t 9 4 2 tt e ve4 1 e ct L ikL t ft wAt 1 d 77 i 77te Ve tL ii 4LL JZ t ii 4 ll a L cSd ej J 1 I aw t J ve4 r LLL Is vt 4 Consider two unequal non zero vectors A and B which are parallel to each other How many statements about these two vectors among the 12 statements below are true A A O A B O A B B A A A Ov A B O A B B A AA O A B O A B BA V AxA O v a 4 b 5 J6 d 7 e 8 CAn3 5 An object is shoved up a rough inclined plane with a large brief initial push As the mass moves up the inclined plane after the initial push what is the correct force diagram for that mass The arrows represent actual physical forces not components B D C E 11 7k 4 c de t e t1 6 Find the angle between two vectors A a b c d e i 2 k and B 21 3 2k 0 64 rad 0 92 rad 1 16 rad 1 37 rad 1 98 rad i An 4 3 i z JT f 31S o 6 7 Each of the three diagrams at right shows consecutive positions of an object circles as well as vectors of its velocity arrows at moments separated by equal time intervals In the order of appearance of the diagrams the total force acting on the object in each situation could be pointing r f a down down down b down down left c zero down right zero up down e zero zero left co i tL v4 7 L J1 a Z t 11 j 4 e i L fr d vf 4 4 ec 61 4d v 6 c LA tLt tt 4 r L VJc4J I 4LI Ck d 01 i frrtkt 8 Three blocks with masses ml 2 kg m2 3 kg and m3 4 kg are in contact on a frictionless tabletop A constant force F 18 N is applied to box in as shown What is the magnitude of the normal force that block m3 exerts on block m2 a b c d e 18N 14N 8N 6N 4N frictionless 4e C t 1 F i te I O1 t 4j 4 t 4 e1 54k 2 0 nkS Secxd AI fmf L1 3 7fl 9 A Physics 140 textbook rests on a horizontal table Which statement about the forces acting on the textbook is true a The weight and the normal force are equal in magnitude and opposite in direction because they are always equal in magnitude and opposite in direction in all situations b The weight and the normal force are equal in magnitude and opposite in direction because they form an action reaction pair and hence by Newton s third law they must be equal and opposite The weight and the normal force are equal in magnitude and opposite in direction because the textbook has no acceleration and hence by Newton s second law the two forces must sum to zero d The weight and the normal force are equal in magnitude and opposite in direction because the textbook is pressing on the table down as strongly as the table is pushing on the textbook up e The weight and the normal force are opposite in direction but not equal in magnitude because the two forces are exerted by different bodies and hence they do not have to be equal to each other 4 k t C 4 cfCt L f4tL 47 ke 4d f P Cc book o 1eok o1 wrf a wMzi la 4 CpIy fr 7e Ce Tke i 4k ZkCL tZCJ 4ct t not O L b t zv be rhJ k 10 Three blocks A B and C each having mass M are connected by massless strings as shown Block C is pulled to the right by a force F that causes the entire system to accelerate on a horizontal tabletop Neglecting friction what is the net force on block B T a 0 F 3 c Ff2 d 2F 3 e F A irr B F C F 4k 3 II A person of mass m stands on a bathroom scale placed on the floor of an elevator The elevator is going up and slowing down with a constant acceleration of magnitude a What is the reading of the bathroom scale The person does not …