PHYSICS FINAL
122) A girl of mass 55 kg throws a ball of mass 0.8 kg against a wall. The ball strikes the wall horizontally with a speed of 25 m/s, and it bounces back with this same speed. The ball is in contact with the wall 0.05 s. What is the average force exerted on the wall by the ball? A) 400 N B) 800 N C) 55,000 N D) 13,750 N E) 27,500 N
B
123) A block of mass m = 3.6 kg, moving on a frictionless surface with a speed vi = 9.3 m/s, makes a perfectly elastic collision with a block of mass M at rest. After the collision, the 3.6 kg block recoils with a speed of vf = 2.7 m/s. In the figure, the speed of the block of mass M after the collision is closest to: A) 9.3 m/s B) 6.6 m/s C) 10.7 m/s D) 12.0 m/s E) 8.0 m/s
B
11) Assuming equal rates of acceleration in both cases, how much further would you travel if braking from 56 mi/h to rest than from 28 mi/h? A) 4.8 times farther B) 3.2 times farther C) 4 times farther D) 5.2 times farther
C
117) A 1200 kg cannon fires a 100.0 kg cannonball at 35 m/s. What is the recoil velocity of the cannon? Assume that frictional forces are negligible and the cannon is fired horizontally. A) 3.2 m/s B) 2.9 m/s C) 35 m/s D) 3.5 m/s
B
109) A steel wire, 3.2 m long, has a diameter of 1.2 mm. The wire stretches 1.6 mm when it bears a load. Young's modulus for steel is 2.0 ×1011 n/m2. The mass of the load is closest to: A) 16 kg B) 20 kg C) 24 kg D) 28 kg E) 12 kg
E
114) A 51 g steel ball is released from rest and falls vertically onto a steel plate. The ball strikes the plate and is in contact with it for 0.5 ms. The ball rebounds elastically, and returns to its original height. The time interval for a round trip is 3.00 s. In this situation, the average force exerted on the ball during contact with the plate is closest to: A) 2000 N B) 1500 N C) 3500 N D) 2490 N E) 3000 N
E
131) Which of the following is a TRUE statement? A) The second law of thermodynamics is a consequence of the first law of thermodynamics. B) It is impossible to transfer heat from a cooler to a hotter body. C) It is not possible to convert work entirely into heat. D) It is possible for heat to flow spontaneously from a hot body to a cold one or from a cold one to a hot one, depending on whether or not the process is reversible or irreversible. E) All of these statements are false.
E
136) An ideal gas is held in a container of volume V at pressure P. The rms speed of a gas molecule under these conditions is v. If now the volume and pressure are changed to 2V and 2P, the rms speed of a molecule will be: A) v B) 1/2 v C) v/4 D) 4v E) 2v
E
138) You may have noticed that when you get out of a swimming pool and stand dripping wet in a light breeze, you feel much colder than you feel after you dry off. Why is this? A) The moisture on your skin has good thermal conductivity. B) The water on your skin is colder than the surrounding air. C) Water has a relatively large heat capacity. D) This is a purely psychological effect resulting from the way in which sensory nerves in the skin are stimulated. E) 540 calories of heat are required to evaporate each gram of water from your skin, and most of this heat flows out of your body.
E
141) A 24 liter tank contains ideal helium gas at 27°C and a pressure of 22.0 Atm. How many moles of gas are in the tank? A) 17.5 moles B) 138 moles C) 76.0 moles D) 238 moles E) 21.5 moles
E
111) A spring stretches by 21.0 cm when a 135 N object is attached. What is the weight of a fish that would stretch the spring by 44.9 cm? A) 289 N B) 405 N C) 63 N D) 176 N
A
101) Through what angle in degrees does a 33 rpm record turn in 0.32 s? A) 74° B) 35° C) 46° D) 63°
D
37) Which of the following is NOT a vector? A) speed B) velocity C) acceleration D) displacement
A
10) A motorist makes a trip of 180 miles. For the first 90 miles she drives at a constant speed of 30 mph. At what constant speed must she drive the remaining distance if her average speed for the total trip is to be 40 mph? A) 60 mph B) 45 mph C) 55 mph D) 50 mph E) 52.5 mph
A
100) A tall tree and a short tree (both having the same width and mass density) are cut at the base at the same time, and begin tipping over. Which tree hits the ground first? A) the small tree B) the tall tree C) They hit at the same time
A
112) An object attached to a spring is pulled across a frictionless surface. If the spring constant is 45 N/m and the spring is stretched by 0.88 m when the object is accelerating at 1.4 m/s2, what is the mass of the object? A) 28 kg B) 36 kg C) 24 kg D) 31 kg
A
126) Joe and Bill throw identical balls vertically upward. Joe throws his ball with an initial speed of twice as high as Bill's ball. The maximum height of Joe's ball will be A) four times that of Bill's ball. B) equal to that of Bill's ball. C) two times that of Bill's ball. D) roughly 1.3 times that of Bill's ball. E) eight times that of Bill's ball.
A
129) A person stands on the edge of a cliff. She throws three identical rocks with the same speed. Rock X is thrown vertically upward, rock Y is thrown horizontally, and rock Z is thrown vertically downward. Assuming the elevation loss of the three rocks is the same (the base of the cliff is flat), which rock hits the ground with the highest speed? A) They all hit the ground with the same speed. B) Rock X C) Rock Y D) Rock Z
A
13) A toy rocket is launched vertically from ground level (y = 0 m), at time t = 0.0 s. The rocket engine provides constant upward acceleration during the burn phase. At the instant of engine burnout, the rocket has risen to 49 m and acquired a velocity of 60 m/s. The rocket continues to rise in unpowered flight, reaches maximum height, and falls back to the ground. The maximum height reached by the rocket is closest to: A) 233 m B) 256 m C) 221 m D) 244 m E) 209 m
A
28) A football kicker is attempting a field goal from 44 m out. The ball is kicked and just clears the lower bar with a time of flight of 2.9 s. If the angle of the kick was 45°, what was the initial speed of the ball? A) 21.5 m/s B) 19.7 m/s C) 39 m/s D) 2.2 m/s
A
36) A projectile is fired from the origin (at y = 0 m) as shown in the figure. The initial velocity components are vox = 940 m/s and voy = 96 m/s. The projectile reaches maximum height at point P, then it falls and strikes the ground at point Q. In the figure, the y-coordinate of point P is closest to: A) 470 m B) 90,160 m C) 45,550 m D) 45,080 m E) 940 m
A
44) A large truck collides head-on with a cyclist. During the collision A) the truck exerts the same amount of force on the cyclist as the cyclist exerts on the truck. B) the truck exerts a force on the cyclist, but the cyclist exerts no force on the truck. C) the truck exerts a smaller amount of force on the cyclist than the cyclist exerts on the truck. D) the truck exerts a greater amount of force on the cyclist than the cyclist exerts on the truck.
A
47) An object is moving with a constant velocity. Which statement(s) MUST be true? A) The net force on the object is zero. B) A small net force is acting on the object, in the direction of motion. C) No forces are acting on the object. D) Two of the above statements are true
A
57) If you jumped out of a plane, you would begin speeding up as you fall downward. Eventually, due to wind resistance, your velocity would become constant with time. After this occurs, the magnitude of the force of wind resistance is A) equal to the force of gravity acting on you. B) is slightly smaller than the force of gravity acting on you. C) is greater than the force of gravity acting on you. D) is much smaller than the force of gravity acting on you.
A
73) A 6.0 kg box is held at rest by two ropes that form 30° angles with the vertical. An external force F acts vertically downward on the box. The force exerted by each of the two ropes is denoted by T. A force diagram, showing the four forces that act on the box in equilibrium, is shown in the figure. The magnitude of force F is 410 N. The magnitude of force T is closest to: A) 271 N B) 376 N C) 470 N D) 235 N E) 188 N
A
82) A person ties a rock to a string and whirls it around in a vertical circle such that sometimes the rock is going straight upward and sometimes the rock is going straight down. She whirls the rock at the minimum speed (constant in time) such that the string is always taut (no sag). When is the tension the highest? A) It is highest when the rock is at the lowest elevation. B) The tension is constant as the rock moves around in a circle. C) It is highest when the rock is at the highest elevationA
A
89) A potter's wheel (a solid, uniform disk) of mass 7.0 kg and radius 0.65 m spins about its central axis. A 2.1 kg lump of clay is dropped onto the wheel at a distance 0.41 m from the axis. Calculate the rotational inertia of the system. A) 1.8 kg ∙ m2 B) 1.5 kg ∙ m2 C) 2.5 kg ∙ m2 D) 0.40 kg ∙ m2
A
99) At time t = 0 s, a wheel has an angular displacement of zero radians and an angular velocity of +14 rad/s. The wheel has a constant acceleration of -0.41 rad/s2. In this situation, the time at which the angular displacement is +88 rad and decreasing is closest to: A) 61 s B) 6 s C) 34 s D) 74 s E) 7 s
A
124) A 5 kg ball collides head-on with a 10 kg ball, which is initially stationary. The collision is inelastic. Which statement is true? A) The magnitude of the change of velocity the 5 kg ball experiences is less than that of the 10 kg ball. B) The magnitude of the change of velocity the 5 kg ball experiences is greater than that of the 10 kg ball. C) The magnitude of the change of the momentum of the 5 kg ball is equal to the magnitude of the change of momentum of the 10 kg ball. D) The magnitude of the change of velocity the 5 kg ball experiences is equal to that of the 10 kg ball. E) Two of the above statements are true.
B
125) Two cyclists, who weigh the same and have identical bicycles, ride up the same mountain, both starting at the same time. Joe rides straight up the mountain, and Bob rides up the longer road that has a lower grade. Joe gets to the top before Bob. Which statement is true? A) Ignoring friction and wind resistance, the amount of work done by Joe is greater than the amount of work done by Bob, and the average power exerted by Joe is greater than that of Bob. B) Ignoring friction and wind resistance, the amount of work done by Joe is equal to the amount of work done by Bob, but the average power exerted by Joe is greater than that of Bob. C) Ignoring friction and wind resistance, the average power exerted by Bob and Joe was the same, but Joe exerted more work in getting there. D) Ignoring friction and wind resistance, Bob and Joe exerted the same amount of work, and the average power of each cyclist was also the same.
B
128) A person drops one rock from rest and it falls 100 meters down a cliff before hitting the ground. The person then throws an identical rock downward. The amount of kinetic energy gained by the rock dropped from rest is _____ that of the second rock, and the magnitude of the change in speed (between hitting the ground and its initial speed) of the rock dropped from rest is _____ that of the second rock. A) less than, less than B) equal to, greater than C) equal to, less than D) equal to, equal to
B
134) An important feature of the Carnot cycle is that A) its efficiency depends only on the absolute temperature of the hot reservoir used. B) no engine can be more efficient than a Carnot engine operating between the same two temperatures. C) its efficiency is determined by the temperatures of the hot and cold reservoirs between which it works and by the properties of the working substance used, and on nothing else. D) its efficiency can be 100%. E) it is an example of an irreversible process that can be analyzed exactly without approximations
B
139) A 2294 kg sample of water at 0°C is cooled to -36°C, and freezes in the process. How much heat is liberated? (For water Lf= 334 kJ/kg and Lv = 2257 kJ/kg. The specific heat for ice is 2050 J/kg ∙ K.) A) 334,000 kJ B) 935,000 kJ C) 597,000 kJ D) 1,110,000 kJ
B
15) A person in a car is driving down a straight road. The instantaneous acceleration is decreasing with time, but is directed in the direction of the car's motion. The speed of the car is A) constant. B) increasing with time. C) decreasing with time
B
17) A car moving at a velocity of 20 m/s is behind a truck moving at a constant velocity of 18 m/s. When the car is 50 m behind the front of the truck, the car accelerates uniformly at 1.8 m/s2. The car continues at the same acceleration until it reaches a velocity of 25 m/s, which is the legal speed limit. The car then continues at a constant velocity of 25 m/s, until it passes the front of the truck. The distance the car travels while accelerating, in meters, is closest to:
B
19) A stone is thrown vertically upwards, reaches a highest point, and returns to the ground. When the stone is at the top of its path, its acceleration A) changes direction from upwards to downwards. B) is directed downwards. C) is zero. D) is directed upward
B
20) A baseball is hit with a bat and, as a result, its direction is completely reversed and its speed is doubled. If the actual contact with the bat lasts 0.45 s, what is the ratio of the acceleration to the original velocity? A) -4.4 s-1 B) -6.7 s-1 C) -2.2 s-1 D) -0.15 s-1
B
23) A ball is projected upward at time t = 0.0 s, from a point on a roof 60 m above the ground. The ball rises, then falls and strikes the ground. The initial velocity of the ball is 28.4 m/s. Consider all quantities as positive in the upward direction. At time t = 4.3 s, the acceleration of the ball is closest to: A) +5 m/s2 B) -10 m/s2 C) zero D) -5 m/s2 E) +10 m/s2
B
26) A car accelerates from 5.0 m/s to 21 m/s at a rate of 3.0 m/s2. How far does it travel while accelerating? A) 117 m B) 69 m C) 41 m D) 207 m
B
30) Which of the following ideas is true about projectile motion with no air drag? A) The velocity of the object is zero at the point of maximum elevation. B) The horizontal motion is independent of the vertical motion. C) The acceleration is +g when the object is rising and -g when falling. D) The trajectory will depend on the object's mass as well as its initial velocity and launch angle. E) ν 2 x + ν 2 y = constant.
B
33) The magnitude of A is 5.5. Vector A lies in the second quadrant and forms an angle of 34 degrees with the y-axis. The components, Ax andAy, are closest to: A) Ax = +3.1, Ay = -4.6 B) Ax = -3.1, Ay = +4.6 C) Ax = -4.6, Ay = +3.1 D) Ax = -4.6, Ay = -3.1 E) Ax = +4.6, Ay = -3.1
B
34) A child is sitting on the outer edge of a merry-go-round that is 18 m in diameter. If the merry-go-round makes 8.3 rev/min, what is the velocity of the child in m/s? A) 5.5 m/s B) 7.8 m/s C) 15.6 m/s D) 1.2 m/s
B
42) A rescue plane spots a survivor 132 m directly below and releases an emergency kit with a parachute. If the package descends at a constant vertical acceleration of 6.89 m/s2 and the initial plane horizontal speed was 68.9 m/s, how far away from the survivor will it hit the waves? A) 446 m B) 426 m C) 2.64 km D) 301 m
B
45) An object is moving to the right, and experiencing a net force that is directed to the right. The magnitude of the force is decreasing with time. The speed of the object is A) constant in time. B) increasing. C) decreasing.
B
46) A small car and an SUV are at a stoplight. The car has a mass equal to half that of the SUV, and the SUV's engine can produce a maximum force equal to twice that of the car. When the light turns green, both drivers floor it at the same time. Which vehicle pulls ahead of the other vehicle after a few seconds? A) the car B) It is a tie. C) the SUV
B
48) Consider what happens when you jump up in the air. Which of the following is the most accurate statement? A) You are able to spring up because the earth exerts a force upward on you which is stronger than the downward force you exert on the earth. B) When you push down on the earth with a force greater than your weight, the earth will push back with the same magnitude force and thus propel you into the air. C) Since the ground is stationary, it cannot exert the upward force necessary to propel you into the air. Instead, it is the internal forces of your muscles acting on your body itself which propels the body into the air. D) It is the upward force exerted by the ground that pushes you up, but this force can never exceed your weight.
B
52) A ball is thrown vertically upward, reaches a highest point, and comes back down. At the top of its path, what forces, if any, act on the ball? Explain your answer. A) no forces B) only a downward force C) only an upward force D) an upward and a downward force, opposing and equal
B
60) A rope is tied to a large crate, which is sitting on a flat surface. The coefficient of static friction between the crate and the ground is 0.9. If a person is to pull on the rope with the minimum force needed such that the crate begins to slide, the angle between the rope and the ground should be A) 90 degrees. B) greater than 0 degrees but less than 90 degrees. C) 0 degrees (rope is horizontal).
B
62) A 200 g hockey puck is launched up a metal ramp that is inclined at a 30° angle. The coefficients of static and kinetic friction between the hockey puck and the metal ramp are "s = 0.40 and "k = 0.30, respectively. The puck's initial speed is 16 m/s. What vertical height does the puck reach above its starting point? A) 13 cm B) 8.6 cm C) 17 cm D) 4.2 cm
B
63) A cyclist is riding up a hill having a constant slope of 30° with respect to the horizon at a constant speed (in a straight line). Which statement is true? A) The net force on the bike (due to gravity, the normal force, and friction) is in the opposite direction of motion. B) The net force on the bike (due to gravity, the normal force, and friction) is zero. C) The net force on the bike (due to gravity, the normal force, and friction) is in the direction of motion. D) None of the above statements are true.
B
86) You need to make a sharp turn on a flat road, making a radius of curvature of 15 meters. How does the required force of static friction between your tires compare if you make the turn at 30 mph vs. 60 mph? A) The force of friction is the same for both speeds since the radius of curvature is the same. B) The force of friction needs to be four times as large. C) The force of friction needs to be twice as large. D) None of the above
B
87) You are the science officer on a visit to a distant solar system. Prior to landing on a planet you measure its diameter to be 1.8 × 107 m. You have previously determined that the planet orbits 2.9 × 1011 m from its star with a period of 402 Earth days. Once on the surface you find that the acceleration due to gravity is 19.5 m/s2. What are the masses of (a) the planet and (b) the star? A) (a) 4.3 kg ×1025 kg (b) 1.2 kg ×1031 kg B) (a) 2.4 kg ×1025 kg (b) 1.2 kg ×1031 kg C) (a) 2.4 kg ×1025 kg (b) 7.1 kg ×1030 kg D) (a) 4.3 kg ×1025 kg (b) 7.1 kg ×1030 kg
B
88) Suppose we want a satellite to revolve around Earth 5 times a day. What should the radius of its orbit be? (Neglect the presence of the Moon.) A) 2.11 × 107 m B) 1.44 × 107 m C) 7.22 × 107 m D) 0.69 × 107 m
B
97) At time t = 0 s, a wheel has an angular displacement of zero radians and an angular velocity of +28 rad/s. The wheel has a constant acceleration of -0.51 rad/s2. In this situation, the time t, at which the wheel comes to a mandatory halt, is closest to: A) 96 s B) 130 s C) 55 s D) 120 s E) 78 s
B
98) A tire is rolling along a road, without slipping, with a velocity v. A piece of tape is attached to the tire. When the tape is opposite the road (at the top of the tire), it's velocity with respect to the road is A) 1.5 v. B) 2 v. C) v. D) The velocity depends on the radius of the tire
B
110) Suppose that a heavy person and a light person are balanced on a teeter-totter made of a plank of wood. Each person now moves in toward the fulcrum a distance of 25 cm. What effect will this have on the balance of the teeter-totter? A) The heavy person's end will go down. B) The teeter-totter will remain in balance. C) The light person's end will go down. D) One cannot tell whether either end will rise or fall without knowing the relative mass of the plank. E) Only if the plank has significant mass will the light person's end go down.
C
115) A block of mass m = 7.6 kg, moving on a frictionless surface with a speed vi = 7.6 m/s, makes a perfectly elastic collision with a block of mass M at rest. After the collision, the 7.6 kg block recoils with a speed of vf = 2.5 m/s. In the figure, the blocks are in contact for 0.20 s. The average force on the 7.6 kg block, while the two blocks are in contact, is closest to: A) 336 N B) 289 N C) 384 N D) 241 N E) 194 N
C
116) A car of mass 1411 kg collides head-on with a parked truck of mass 2000 kg. Spring mounted bumpers ensure that the collision is essentially elastic. If the velocity of the truck is 17 km/h (in the same direction as the car's initial velocity) after the collision, what is the initial speed of the car? A) 32 km/h B) 11 km/h C) 21 km/h D) 42 km/h
C
12) A car moving at a velocity of 20 m/s is behind a truck moving at a constant velocity of 18 m/s. When the car is 50 m behind the front of the truck, the car accelerates uniformly at 1.8 m/s2. The car continues at the same acceleration until it reaches a velocity of 25 m/s, which is the legal speed limit. The car then continues at a constant velocity of 25 m/s, until it passes the front of the truck. The distance the car travels while accelerating, in meters, is closest to: A) 54 B) 66 C) 62 D) 50 E) 58
C
137) An ideal gas inside box A of volume V has a temperature T and contains N molecules. An ideal gas inside box B of volume V/2 has a temperature T/2, and also contains N molecules. In which box is the pressure the highest? A) Box B B) Box A C) The pressure is the same in both boxes
C
14) A train starts from rest and accelerates uniformly, until it has traveled 2.1 km and acquired a velocity of 24 m/s. The train then moves at a constant velocity of 24 m/s for 400 s. The train then slows down uniformly at 0.065 m/s2, until it is brought to a halt. The distance traveled by the train while slowing down, in km, is closest to: A) 3.8 B) 3.6 C) 4.4 D) 4.0 E) 4.2
C
144) Which of the following is a FALSE statement? A) Heat is energy transferred into or out of a system as a result of a temperature difference between the system and its surroundings. B) When an ideal gas experiences a free expansion, its temperature doesn't change. C) The heat added to an ideal gas during the transition from state 1 to state 2 depends only on the initial and final states, 1 and 2, and not on the path by which the gas went from one to the other. D) When a gas goes from one state to another, the work done depends on the path followed. E) It does not make sense to refer to "the amount of heat in a body."
C
146) Calculate the pressure exerted on the ground by a 79 kg person standing on one foot. Assume that the bottom of the person's foot is 13 cm wide and 28 cm long. A) 5.3 × 104 Pa B) 4.8 × 104 Pa C) 2.1 × 104 Pa D) 2.2 × 103 Pa
C
21) A ball is projected upward at time t = 0.0 s, from a point on a roof 90 m above the ground. The ball rises, then falls and strikes the ground. The initial velocity of the ball is 80.5 m/s. Consider all quantities as positive in the upward direction. The velocity of the ball when it is 89 m above the ground is closest to: A) -64 m/s B) -48 m/s C) -81 m/s D) -97 m/s
C
27) A toy rocket is launched vertically from ground level (y = 0 m), at time t = 0.0 s. The rocket engine provides constant upward acceleration during the burn phase. At the instant of engine burnout, the rocket has risen to 81 m and acquired a velocity of 40 m/s. The rocket continues to rise in unpowered flight, reaches maximum height, and falls back to the ground. The upward acceleration of the rocket during the burn phase is closest to: A) 9.0 m/s2 B) 9.6 m/s2 C) 9.9 m/s2 D) 9.3 m/s2 E) 8.7 m/s2
C
39) Two bullets are fired simultaneously parallel to a horizontal plane. The bullets have different masses and different initial velocities. Which one will strike the plane first? A) the lightest one B) the heaviest one C) They strike the plane at the same time. D) the fastest one E) the slowest one
C
49) Joe and Bill are playing tug-of-war. Joe is pulling with a force of 200 N. Bill is simply hanging on to the rope. Neither person is moving. What is the tension of the rope? A) 0 N B) 300 N C) 200 N D) 400 N
C
51) A stalled car is being pushed up a hill by three people, and it is moving at a constant speed. The net force on the car is A) in the same direction of the car's motion. B) in the opposite direction of the car's motion. C) zero. D) None of the above
C
54) A person gives a shopping cart an initial push along a horizontal floor to get it moving, and then lets go. The cart travels forward along the floor, gradually slowing as it moves. Consider the horizontal force(s) on the cart while it is moving forward and slowing. Which of the following statements is correct? A) Both a forward and a backward force are acting on the cart, but the backward force is larger. B) Only a forward force is acting, which diminishes with time. C) Only a backward force is acting, no forward force. D) Both a forward and a backward force are acting on the cart, but the forward force is larger.
C
55) You are making a circular turn in your car when you hit a big patch of ice, causing the force of friction between the tires and the road to become zero. While the car is on the ice, it A) moves along a path that is neither straight nor circular. B) continues to follow the same circular path as initially. C) moves along a straight-line path. D) continues to follow a circular path, but with a radius larger than the original radi
C
56) Suppose you are playing hockey on a new-age ice surface in which there is no friction between the ice and the hockey puck. You wind up and hit the puck as hard as you can. Just after the puck loses contact with your stick, the puck A) will speed up a little, and then move at a constant speed. B) will speed up a little, and then slow down. C) will not slow down or speed up. D) will start to slow down
C
58) An object is moving to the right in a straight line. The net force acting on the object is also directed to the right, but the magnitude of the force is decreasing with time. The object will A) continue to move to the right with a constant speed. B) stop and then begin moving to the left. C) continue to move to the right, with its speed increasing with time. D) continue to move to the right, with its speed decreasing with time.
C
75) A person ties a rock to a string and whirls it around in a vertical circle such that sometimes the rock is going straight upward and sometimes the rock is going straight down. She whirls the rock at the minimum speed (constant in time) such that the string is always taut (no sag). If she were to use a longer string, she would have to whirl the rock at a A) the same velocity. B) lower velocity. C) higher velocity
C
79) If an astronaut were exactly half way between Earth and the Moon, the net gravitational force exerted on the astronaut by these two objects would be A) zero. B) directed toward the Moon. C) directed toward Earth.
C
85) A proton moving at 0.999 of the speed of light orbits a black hole 4972 km from the center of the attractor. What is the mass of the black hole? A) 6.71 × 1036 kg B) 6.71 × 1025 kg C) 6.71 × 1033 kg D) 6.71 × 1030 kg
C
91) A force of 17 N is applied to the end of a 0.63 m long torque wrench at an angle 45° from a line joining the pivot point to the handle. What is the magnitude of the torque generated about the pivot point? A) 10.7 N∙m B) 12.0 N∙m C) 7.6 N∙m D) 9.7 N∙m
C
94) In the figure, a mass of 35.30 kg is attached to a light string that is wrapped around a cylindrical spool of radius 10 cm and moment of inertia 4.00 kg ∙ m2. The spool is suspended from the ceiling, and the mass is then released from rest a distance 3.50 m above the floor. How long does it take to reach the floor? A) 2.85 s B) 0.892 s C) 2.97 s D) 4.18 s E) 5.89 s
C
95) A force of 16.88 N is applied tangentially to a wheel of radius 0.340 m and gives rise to an angular acceleration of 1.20 rad/s2. Calculate the rotational inertia of the wheel. A) 7.17 kg ∙ m2 B) 5.98 kg ∙ m2 C) 4.78 kg ∙ m2 D) 3.59 kg ∙ m2
C
102) A man pushes against a rigid, immovable wall. Which of the following is the most accurate statement concerning this situation? A) Since the wall cannot move, it cannot exert any force on the man. B) The friction force on the man's feet is directed to the left. C) The man cannot be in equilibrium since he is exerting a net force on the wall. D) If the man pushes on the wall with a force of 200 N, we can be sure that the wall is pushing back with a force of exactly 200 N on him. E) The man can never exert a force on the wall that exceeds his weight
D
127) Three cars (car F, car G, and car H) are moving with the same velocity, and slam on the brakes. The most massive car is car F, and the least massive is car H. Assuming all three cars have identical tires, which car travels the longest distance to skid to a stop? A) Car G. B) Car H. C) Car F. D) They all travel the same distance in stopping.
D
133) What is the maximum efficiency of an engine operating between a reservoir in which ice and water coexist, and a reservoir in which water and steam coexist? The pressure is constant at 1.0 atmosphere for both. A) 1.0% B) 100% C) 0.27% D) 27%
D
135) Which of the following is a FALSE statement? A) Entropy can be measured in units of J/K. B) Entropy is a quantitative measure of disorder. C) The total entropy change in one cycle of a Carnot engine is zero. D) The entropy of an isolated system is conserved, i.e., constant.
D
142) An aluminum rod is 10.0 cm long and a steel rod is 80.0 cm long when both rods are at a temperature of 15°C. Both rods have the same diameter. The rods are joined end-to-end to form a rod 60.0 cm long. The coefficients of linear expansion of aluminum and steel are 2.4 ×10-5 K-1 and 1.2 ×10-5 K-1, respectively. The temperature is raised to 90°C. The increase in the length of the joined rod, in mm, is closest to: A) 0.63 B) 0.81 C) 0.99 D) 0.90 E) 0.72
D
143) In years of heavy snow pack in the mountains it is sometimes desirable to induce early melting of the snow, rather than wait until it all melts suddenly and causes floods. It has been suggested that a way to accomplish this might be to have planes fly over the snow fields and sprinkle them with black soot. What do you think of this idea? Would it work? A) No, it would not work because sunlight has very little effect on how fast the snow melts. B) Yes, it would work because the soot would decrease the specific heat capacity of the snow. C) Yes, it would work because the soot would raise the melting point of the snow. D) Yes, it would probably work because the black surface would be a better absorber of sunlight than would the white snow. E) No, it would not work because it is infrared radiation and not visible radiation which melts the snow
D
145) A barge loaded with lumber and iron ore floats in a lock by a dam (a closed pool of water like a big swimming pool). If some of the cargo is thrown overboard, the level of water in the lock will A) rise. B) rise, provided it is iron ore that is thrown overboard. C) drop. D) stay the same. E) rise, provided it is lumber that is thrown overboard
D
16) A train starts from rest and accelerates uniformly, until it has traveled 5.6 km and acquired a velocity of 42 m/s. The train then moves at a constant velocity of 42 m/s for 420 s. The train then slows down uniformly at 0.065 m/s2, until it is brought to a halt. The acceleration during the first 5.6 km of travel is closest to: A) 0.19 m/s2 B) 0.20 m/s2 C) 0.14 m/s2 D) 0.16 m/s2 E) 0.17 m/s2
D
24) A toy rocket is launched vertically from ground level (y = 0 m), at time t = 0.0 s. The rocket engine provides constant upward acceleration during the burn phase. At the instant of engine burnout, the rocket has risen to 64 m and acquired a velocity of 60 m/s. The rocket continues to rise in unpowered flight, reaches maximum height, and falls back to the ground. The time interval, during which the rocket engine provides upward acceleration, is closest to: A) 1.9 s B) 1.7 s C) 1.5 s D) 2.1 s E) 2.3 s
D
38) A cat leaps to catch a bird. If the cat's jump was at 60.0° off the ground and its initial velocity was 2.74 m/s, what is the highest point of its trajectory? A) 0.19 m B) 10.96 m C) 0.58 m D) 0.29 m
D
41) Two particles, A and B, are in uniform circular motion about a common center. The acceleration of particle A is 4.7 times that of particle B. Particle B takes 2.4 times as long for a rotation as particle A. The ratio of the radius of the motion of particle A to that of particle B is closest to: A) 3.8 B) 11 C) 2.0 D) 0.82 E) 0.51 4
D
61) What is the mass of an object that experiences a gravitational force of 685 N near Earth's surface? A) 71.3 kg B) 68.5 kg C) 72.7 kg D) 69.9 kg
D
68) A 22 kg box must be slid across the floor. If the coefficient of static friction between the box and floor is 0.37, what is the minimum force needed to start the box moving from rest? A) 56 N B) 216 N C) 112 N D) 80 N
D
72) If you were to move into outer space far from any stars or planets, A) both your weight and mass would change. B) your mass would change, but your weight would not change. C) neither your weight nor your mass would change. D) your weight would change, but your mass would not change. E) None of these is true.
D
77) Future space stations will create an artificial gravity by rotating. Consider a cylindrical space station of 380 m diameter rotating about its axis. Astronauts walk on the inside surface of the space station. What rotation period will provide "normal" gravity? A) 6.2 s B) 4.4 s C) 39 s D) 28 s
D
80) What is the gravitational force acting on a person due to another person standing 2 meters away? Assume each individual has 59 kg mass. A) 8.5 × 103 N B) 2.0 × 10-9 N C) 1.2 × 10-7 N D) 5.8 × 10-8 N
D
81) If the Moon were twice the distance from Earth than it currently is, the amount of time it would take to go around Earth would be roughly (the current orbital period of the Moon is four weeks) A) eight weeks. B) six weeks. C) 88 weeks. D) 11 weeks.
D
83) At a given point above the surface of Earth, the gravitational acceleration is equal to 7.8 m/s2. The altitude of this point, above the surface of Earth, in km, is closest to: A) 2000 B) 1500 C) 970 D) 770
D
9) Two identical stones are dropped from a tall building, one after the other. Assume air resistance is negligible. While both stones are falling, what will happen to the vertical distance between them? A) It will first increase and then remain constant. B) It will decrease. C) It will remain the same. D) It will increase.
D
90) A machinist turns the power on to a grinding wheel, at rest, at time t = 0 s. The wheel accelerates uniformly for 10 s and reaches the operating angular velocity of 96 rad/s. The wheel is run at that angular velocity for 40 s and then power is shut off. The wheel slows down uniformly at 1.5 rad/s2 until the wheel stops. In this situation, the time interval of deceleration is closest to: A) 70 s B) 68 s C) 66 s D) 64 s E) 62 s
D
92) A machinist turns the power on to a grinding wheel, at rest, at time t = 0 s. The wheel accelerates uniformly for 10 s and reaches the operating angular velocity of 29 rad/s. The wheel is run at that angular velocity for 27 s and then power is shut off. The wheel slows down uniformly at 2.7 rad/s2 until the wheel stops. In this situation, the average angular velocity in the time interval from t = 0 s to t = 25 s is closest to: A) 15 rad/s B) 13 rad/s C) 8.7 rad/s D) 17 rad/s E) 11 rad/s
D
140) A glass flask has a volume of 500 ml at a temperature of 20°C. The flask contains 492 ml of mercury at an equilibrium temperature of 20°C. The temperature is raised until the mercury reaches the 500 ml reference mark. The coefficients of volume expansion of mercury and glass are 18 ×10-5 K-1 and 2.0 ×10-5 K-1, respectively. The temperature at which this occurs, in °C, is closest to: A) 112 B) 102 C) 132 D) 110 E) 122
E
