PHYSICS 207 Test 2 = This is an open-book test = 1) The tangential speed and centripetal acceleration of a car going through a turn of fixed radius rad of the turn? (Take g = 10 m/s'.) respectively, v = 100 m/s and ac = 4g (i.e. four times the acceleration due to gravity). What is the radius [A] 1000 m [B] 500 m C 250 m [D] 100 m [E] 50 m 2) A large carnival ride consists of a chair that is swung in a circle, in the horizontal plane, by a cable making an angle of 750 with respect to the vertical pole. What is the tension tension in the cable if the mass of the chair and its occupant is 120 kg? (Take g = ike g = 10 m/s'.) [A] 1150 N [B] 500 N [C] 2400 N [D] 1200 N [E] 1386 N 3) Two banked curves have the same radius but different bank angles, as follows: Curve A has angle 30 eed of 20 m/s. What is the max speed and Curve B has angle 45. Curve A is rated for a maximum speed of rating for Curve B? (Neglect friction of any kind.) [A] 26.32 m/s [B] 280 m/s [C] 2.00 m/s [D] 300 m/s [E] 19 m/s 4) A fighter jet is launched from an aircraft carrier by means of a catapult and its own jet engine's thrust. In being launched from rest, it moves through a distance of 100 m and has a kinetic energy of 5 x 10' J. at lift-off. If the engine provides a thrust force of 105 N, what is the work done on the jet by the catapult? [A] 5 X 107 J [B] 4 X 10' J [C] 500 J [D] 1 x 10' J [E] 100 J 5) A boulder falls vertically from 10 m to the ground. The change in the boulder's potential energy during the fall is APE = - 5000 J. What is its mass? (Take g = 10 m/s'.) [A] 500 kg [B] 25 kg [C] 5 kg [D] 300 kg [E] 50 kg 6) A 20-kg sled is being pulled along a horizontal snow-covered road by a horizontal force. Starting from rest, the sled attains a speed of 5 m/s. What is the total work done on the sled? [A] OJ [B] 50 J [C] 250 J [D] 500 J [E] 1000 J 7) A stream of water enters a 90 elbow joint with constant speed v = 20 m/s. If the stream flows through the pipe with a rate R. = 5 kg/s, find the magnitude of the force experienced by the elbow joint? (Hint: although the speed is constant, the velocity changes between inlet and outlet hence so does the momentum.) [A] 1230 N [B] 3N [C] 100 N [D] 141 N [E] 70 N8) In which one of the following cases is it possible for the total mechanical energy to not be conserved, even in the absence of friction and air resistance? [A] A car moves down a hill, its speed continually increasing along the way. [B] A car moves up a hill, its speed continually decreasing along the way. [C] A car moves along level ground at constant velocity. [D] A car is stationary. TE) A car moves up a hill at constant velocity. 9) A person is riding in a Ferris wheel. When the wheel makes a complete turn, what can you say about the net work done by gravity on the person? (Only one choice is correct.) [A] It is positive. [B] It is negative. [C] It depends on the size of the wheel. (D) It is zero. [E] Depends on how fast the wheel rotates. 10) A car is moving with speed v on a banked track of radius r on the Moon. How does the fact that the Moon's gravity is about 6 times weaker than Earth's (gMoon ~ 1.6 m/s?) affect the centripetal force, when compared to the same conditions (speed, radius) on Earth? [A] The centripetal force on the Moon is stroner than on Earth. [B] The centripetal force on the Moon is weaker than on Earth. [C] Gravity has no effect