PHYSICS 231 MIDTERM II Form B November 4 2002 Name PID Sec Useful constants water 1000 kg m3 g 9 8 m s2 1 hp 746 W Rearth 6 38x106 m G 6 67x1011 Nm2 kg2 g 9 81 m s2 kB 1 38x10 23 J degK Absolute Zero 273 15 degC For each problem choose the most nearly correct answer Answer Key at End 1 A new planet Horatio has been discovered which is four times as far from the sun as Earth What is the period of Horatio s orbit a 8 years b 4 years c 2 years d 1 year e 6 months 2 A hollow cylinder starts from rest at the top of an inclined plan and rolls down The height of the inclined plane is h 5 m and it makes an angle of 30 with respect to the horizontal What is the translational velocity of the cylinder when it reaches the bottom The moment of inertia of a hollow cylinder is I MR2 a 10 0 m s b 8 4 m s c 7 0 m s d 4 2 m s e 2 1 m s PHYSICS 231 MIDTERM II Form B November 4 2002 3 A copper wire of length 4 meters cross sectional area 7 1 10 6 m2 and Young s modulus 11 1010 N m2 has a 300 kg load hung on it Its increase in length L is 5 0 mm Now the wire is cut to a quarter of its original length to 1m and the load is increased to 600 kg What is the increase in length L a 1 25 mm b 2 5 mm c 1 0 cm d 5 0 mm e 0 625 mm 4 A block is dropped from a height h 8000 km above Earth s surface Neglecting Earth s rotation and neglecting air resistance which expression s gives the velocity of the block when it strikes the surface R refers to Earth s radius a v 2 2 GM GM R h R b v 2 2 gh c v 2 g R h d All the above expressions work e None of the expressions work because the answer depends on the mass of the block 5 An object of mass m moves with a velocity of v It collides head on with an object of mass 3m moving with speed 2v 3 in the opposite direction If the two objects stick together what is the velocity magnitude and direction of the combined object after the collision a 0 b v 2 c v 4 d v 2 e v 4 PHYSICS 231 MIDTERM II Form B November 4 2002 6 In a ballistic pendulum experiment two processes occur in succession 1 A bullet at high initial velocity v0 is stopped in a wooden block which is suspended from the ceiling by a string and the combined system acquires a velocity of V and 2 the system executes a pendulum motion in which the velocity decreases as the pendulum rises until it reaches a maximum height and turns back Linear momentum along the direction of motion is conserved in a b c d e process 2 but not 1 process 1 but not 2 both 1 and 2 neither 1 nor 2 none of the above 1 2 7 Each of the three cylinders pictured in the accompanying figure has the same mass and each cylinder s mass is uniformly distributed throughout the colored regions Order the cylinders according to their moment of inertia with the largest moment of inertia being first Assume that the reference axis passes through the center of each cylinder and points out of the page a b c d e large solid cylinder large hollow cylinder small cylinder large hollow cylinder large solid cylinder small cylinder small cylinder large hollow cylinder large solid cylinder large solid cylinder small cylinder large hollow cylinder large hollow cylinder small cylinder large solid cylinder PHYSICS 231 MIDTERM II Form B November 4 2002 8 Consider a light beam hung by two cables as shown above A weight Mg 8000 N is hung as shown What is the tension TR in the right side cable a 10400 N b 6333 N c 5600 N d 4000 N e 3200 N 9 A helicopter suspends a 2000 N probe into Lake Michigan by a cable After the weight is submerged the tension in the cable is 800 N What is the average density of the probe a 2800 kg m3 b 3000 kg m3 c 2500 kg m3 d 1667 kg m3 e 2111 kg m3 10 An incompressible fluid moves through a pipe that has a radius of 30 cm at point A and then narrows to a radius of 20 cm at point B Which of the following is true Assume non viscous laminar flow a The amount of mass that passes A in one second equals the amount of mass that passes B in the same time b The velocity of the fluid at A equals the velocity of the fluid at B c The pressure of the fluid at A equals the pressure at point B d The kinetic energy density at A equals the kinetic energy density at B e The pressure is larger at point B than at A PHYSICS 231 MIDTERM II Form B November 4 2002 11 A leak proof cylinder with a movable piston is filled with helium gas and compressed at a constant pressure of 2 atm The initial temperature is 0 C and the initial volume is 20 L The final volume is 10 L Find the temperature of the gas after the compression a b c d e 0 C 546 3 C 32 C 40 C 136 6 C 12 The r m s velocity of molecules in an ideal gas is measured to be 8000 m s when the temperature is 50 C The gas is then compressed to half its original volume while keeping the temperature fixed at 50 C What is the r m s velocity of the molecules in the compressed gas a 8000 m s b 1 60x104 m s c 4000 m s d 1 13x104 m s e 5657 m s Answers 1 a 2 c 3 b 4 a 5 e 6 b 7 b 8 c 9 d 10 a 11 e 12 a
View Full Document
Unlocking...