MMSTC PHYSICS FINAL EXAM REVIEW 1) The SI unit of momentum is. (kg*m/s or N*s)

Transcription

1 1) The SI unit of momentum is. (kg*m/s or N*s) 2) If the momentum of a bullet is considered positive, the momentum of the gun that fired must be considered. (NEGATIVE) 3) The quantity of motion is called. (MOMENTUM) 4) During a collision when a car comes to a sudden stop, the crumple zone of the car reduces the of a collision. (FORCE) 5) A change in direction is a change in momentum. (Explain) (momentum is a vector quanitity) 6) An airbag in your car increases the of a collision. (TIME) 7) A 4 lb Basketball moving at 4 m/s to the right bounces off a 1275 lb truck at rest and moves at 4 m/s in the opposite direction. This is what type of collision? (ELASTIC) 8) A 175 lb running back moving at 8 m/s to the right collides with 216 lb Liebacker at rest. They Stick together and travel at a slower speed. This is what type of collision. (INELASTIC) 9) Two ice skaters initially at rest push off each other, their final total momentum after they push off is. (ZERO) 10) If two billiard balls collide and move of in different directions, the vector sum of momentum after the collision is the momentum before the collision (EQUAL TO) 11) A Ball with 25 kg m/s of momentum collides with a ball of mass 6 kg initially at rest. After the collision the momentum of the 6 kg ball is 10 kg m/s. What is the momentum of the first ball after the collision? 15 kg*m/s 12) Tennis Players are told to follow through on a swing as they apply a constant force because this allows them to apply a greater. (IMPULSE or CHANGE IN MOMENTUM) 13) To reduce the risk of injury in a collision it is best to increase the of the collision. (TIME) 14) A 45 lb catfish sliding along frictionless ice at 44 m/s to the right collides with 22 lb puppy at rest. They Stick together and travel at a 70 m/s This is what type of collision? (IMPOSSIBLE) 15) The momentum of a large bowling is transferred to a tiny golf ball. The velocity of golf ball is the bowling ball, (GREATER THAN) 16) A person is standing on a skateboard holding a heavy medicine ball. He throws the ball forward, he will move (BACKWARDS) 1

2 17) A 10 kg ball moving at +4 m/s collides with a ball of unknown mass initially at rest. The collision is Elastic. The 10 kg ball slows to +2 m/s. The velocity of the unknown mass after the collision is. (+6 m/s) 18) A small deer collides with a large tiger and sticks to the tiger. Which one experiences the larger magnitude of momentum change? (BOTH THE SAME) 19) A 54 kg*m/s Impulse is applied to a 6 kg object, the change in momentum is. (54 kg*m/s) 20) A 250 lb person moving at 4 m/s to the right collides with a 100 lb person moving at 8 m/s to the left. They stick together and move in which direction? (RIGHT) 21) One half a rotation is equal to radians. (3.14) 22) Which Lever shown has the smallest non-zero torque? (D) 23) Which Lever shown has the largest lever arm? (A) 24) Which lever exerts zero torque? (E,F) 25) Where should you push on a door to apply the least amount off torque when opening the door? (AT THE HINGES) 26) If the angular displacement of rolling wheel is π, and the radius is 2. what is the translational displacement of the wheel? (6.28m) 27) Two equal forces are applied to a door at the doorknob. The first force is applied perpendicular to the door; the second force is applied at 30 to the plane of the door. Which force exerts the smaller torque? (THE FORCE EXERTED AT 30 ) 28) Wrench A is 6 cm long and wrench B is 24 cm long. For a given input force, how does the maximum torque of wrench B compare to the maximum torque of wrench A? (4 x greater (longer lever arm)) 2

3 29) If the linear velocity of a wheel is 4 and the radius is 2, then the angular velocity of the wheel is. (2 rad/s) 30) The SI unit of Torque is. (N*m) 31) Torque is the product of and. (FORCE & LEVER ARM) 32) If a constant Net Torque is applied to an object, that object will. (have angular acceleration) 33) EXPLAIN: A point on a rotating wheel can have zero angular acceleration and NON-zero centripetal acceleration. (centripetal acc depends on velocity, angular acc is a CHANGE in velocity) 34) A boy and a girl are riding on a merry-go-round which is turning at a constant rate. The boy is near the outer edge, and the girl is closer to the center. Who has the smaller angular speed? (SAME SPEED) 35) A boy and a girl are riding on a merry-go-round which is turning at a constant rate. The boy is near the outer edge, and the girl is closer to the center. Who has the smaller linear speed? (THE Girl) 36) An objects Resistance to a changes in Rotational Motion is called. (MOMENT OF INERTIA) 37) What is a measure of the ability of a force to rotate or accelerate an object around an axis? (TORQUE) 38) Angular displacement can be expressed in units of (Radians (SI unit) or Rotations) 39) The torque applied to a lever is maximum at which angle? Check all that apply (90 degrees) 40) Negative torque is always in which direction? (Clockwise) 41) Particle X with a charge of 3.0μC is brought near Particle Y with a charge of 6.0 μc. Which one, if any, experiences a greater force? (BOTH THE SAME) 42) An electron is place in the Electric Field shown below, what direction will it move? (UP) 43) Which end of the Electric Field has a higher potential? (The positive side) 44) Which end of the Electric Field above has a higher potential? (The positive side) 45) One joule per coulomb is a (1 VOLT, Electric Potential) 3

4 46) A positively charged rod is brought near one end of an uncharged metal bar. The end of the metal bar farthest from the charged rod will have what type of charge? (POSITIVE) 47) Two charges are separated by a distance d and exert mutual attractive forces of F on each other. If the charges are separated by a distance of d/4, what are the new mutual forces? (16F) 48) Force per unit charge is called. (ELECTRIC FIELD) 49) A repelling force between two charges occurs when. (THEY HAVE THE SAME CHARGE) 50) A glass rod is rubbed with silk and becomes positively charged, describe happens to electrons during this process. (ELECTRONS ARE REMOVED FROM THE ROD) 51) The distance between two charges is reduced to ½ the original distance, the force between the charges changes by what factor? (4 times greater) 52) What direction is the Force on q2 in the diagram below? ( ) 53) Is it possible to have a zero electric field value between two positive charges along the line joining the two charges? Explain (YES, Forces always oppose each other) 54) Change in Potential Energy per Unit Charge is also known as what term? (POTENTIAL DIFFERENCE, VOLTAGE) 55) What is the sign of each charge (Q1, Q2, Q3) in the diagram above? (Q1+, Q2-, Q3+) 56) A positively charged rod is brought near a neutral sphere. Sketch a diagram of the charges on the sphere as the rod is held near the sphere. (see notes) 57) To measure the current through a resistor using a ammeter, place the ammeter to the resistor in the circuit. (SERIES) 58) What is 1 V A equivalent to what unit of measure? (1 WATT) 59) As the temperature of a wire decreases, How does the resistance of the wire change? (DECREASES) 4

5 60) If you increase the resistance in a circuit while keeping the same potential difference, what happens to the current? (DECREASES) 61) A 100 watts light bulb runs for 3 minutes, how many joules per second does it use? (100W) 62) If you double the current in a circuit while keeping the same potential difference, the power dissipated in the circuit. (DOUBLES) 63) A kilowatt-hour is equivalent to how many joules? ( J) 64) A 2.0 Ω resistor and a 5.0 Ω resistor connected in a parallel circuit. How does the potential difference across the 2.0 Ω resistor compare to the potential difference across the 5.0 Ω resistor. (EQUAL) 65) The resistance of a wire depends on what factors? (material, area, length, temp) 66) Three identical resistors are connected in series to a 9-V battery. What is the voltage across any one of the resistors? (3V) 67) Two resistors of equal size are connected in series; how does the Equivalent resistance of the circuit compare to the resistance of one individual resistor. (GREATER) 68) What is 1 V/A equivalent to what unit of measure? ( 1OHM) 69) A 2.0 Ω resistor and a 5.0 Ω resistor connected in a parallel circuit. How does the current through the 2.0 Ω resistors compare to the current of the 5.0 Ω resistor? (Greater current in the 2 ohm) 70) The direction of conventional current is taken to be the direction which charges travel? (POSITIVE) 71) A 2.0 Ω resistor and a 5.0 Ω resistor connected in a series circuit. How does the potential difference across the 2.0 Ω resistor compare to the potential difference across the 5.0 Ω resistor. (SAME CURRENT) 72) Three identical resistors are connected in parallel to a 6-V battery. What is the voltage of any one of the resistors? (6V) 73) As more resistors are added in series to a constant voltage source, how the power supplied by the source change? (DECREASES) 74) Three identical resistors are connected in parallel to a battery. If the current of 0.75 A flows from the battery, how much current flows through any one of the resistors? (0.25A) 75) Several resistors are wired in a circuit so that there is a single path for the flow of electric current. What type of circuit is this? (SERIES) 76) The sum of the currents through each of the resistors is equal to the total circuit. What type of circuit is this? (PARALLEL) 77) The number of times a particle oscillates in one second is the waves. (FREQUENCY) 78) Harmonics in a(n) pipe instrument can be heard at only odd multiples of the fundamental tone. (CLOSED PIPE) 5

6 79) is the inverse of the frequency. (PERIOD) 80) Two pulses travel through a single slinky, one has amplitude of +20 cm, and the other has amplitude of +15cm. The +15cm pulse reflects off a rigid barrier. The resultant pulse due to interference will have amplitude of. (+5 cm) 81) If you double the wavelength of a wave a single medium, the frequency of the wave. (reduces to ½) 82) The displacement of a wave is not inversed when reflecting from a barrier. (NON-RIGID) 83) The amplitude of a mechanical wave depends on the of a wave. (ENERGY) 84) The determines the energy of a electromagnetic wave. (FREQUENCY) 85) What type of light reflection occurs when light is reflected from a smooth surface? (SPECULAR) 86) The velocity of sound in space is. (ZERO) 87) As an airplane flies away from you, the apparent frequency of the engine noise heard is than the actual. (LOWER) 88) Resonance in a Open Pipe occurs when a a wave reflects off a(n) on each end. (ANTINODE) 89) Resonance in a Closed Pipe occurs when a wave reflects off a(n) at the closed end. (NODE) 90) As the temperature of the air decreases, what happens to the velocity of sound? (Assume that all other factors remain constant.) (DECREASES) 91) Which of the following factors change as light waves pass from one transparent medium into another? (check all that apply) (VELOCITY, WAVELENGTH) 92) The index of refraction is the ratio of what? (Speed of light in a vacuum/speed of light in a material) 93) In a wave, the medium moves parallel to the direction of a wave. (LONGITUDINAL) 94) When sound passes from air into water. ((VELOCITY & WAVELENGTH INCREASES) 95) According to the law of reflection, the angle of incidence is the angle of reflection. (EQUALS) 96) The determines the energy of a mechanical wave. (AMPLITUDE) 97) Which of the following increases as a sound becomes louder? (INTENSITY, AMPLITUDE) 6

7 98) is the bending of light as it enters a new medium. (REFRACTION) 99) What type of light reflection occurs when light is reflected from a smooth surface? A) diverse B) variegated C) specular D) diffuse 100) A laser beam strikes a plane's reflecting surface with an angle of incidence of 30. What is the angle between the incident ray and the reflected ray? (60 ) 101) The index of refraction of a material is always one. (check all that apply) 102) Which substance shown has the highest index of Refraction? (medium 1) 103) Which substance shown has the highest speed of light? (medium 2) PART B: Answer the Following Questions on the back of your answer sheets 1) A 750 kg car moving at 30 m/s is stopped by a 7000N force. A) What is the change in momentum of the car? N*s b) How long does it take to come to rest? 3.21 s c) What distance does it travel? 48.15m 2) A 0.12 kg hockey puck moving at 18 m/s is blocked and hit back at 12 m/s in the opposite direction. A) What is the change in momentum of the puck? 3.6 N*s, B) If it is on the goalies stick for 0.08 s, how much force was exerted on the puck? 45N 3) A 70 gram bullet is fired from 1.5 kg hand gun with a velocity of 250 m/s. What is the velocity and direction of the gun after it is fired? m/s 4) A 1400 kg Ford Tempo moving at 20 m/s hit a 750 kg KIA at moving at 10 m/s in the same direction. If they stick together, what speed are they moving? 16.5 m/s 7

8 5) A bowling ball, (m=4.0 kg) rolling at 8.0 m/s hit a stationary Bowling pin with a mass of 1.6 kg. If it is a completely Elastic collision. a) What is the velocity of pin? PIN = m/s) b) What is the velocity of the ball? BALL = 3.42 m/s 6) A 60 kg biker moving 15m/s due east collides with a 80 kg roller skater moving 10 m/s due north. If they are both move as one after the collision. A) Show the total momentum using a vector addition diagram. B) What speed are they moving? 8.6 m/s C) What direction are they moving? 41.6 degrees 7) A bowling ball, (m=4.0 kg) rolling at 4.0 m/s hits a stationary Bowling pin with a mass of 1.6 kg, the bowing ball moves off at 30 o from it's original direction at 2.0 m/s. A) Show the total momentum using a vector addition diagram. B) What speed does the pin travel? 6.2 m/s C) What direction does the pin travel? 23.8 degrees 9) The 12 inch (30 cm diameter) single extended dance mix version of the Peanut Butter Jelly Song spins at a constant rate of 78 rpm. a) What is the angular velocity at the outside edge of the record? 8.16 rad/s b) What is the tangential acceleration at the outside of the record? zero c) What is the centripetal acceleration at the out side edge of the record? m/s2 9) A 20 inch (radius of wheels = 0.25m) bike starts from rest and rolls forward 30 m in 8.0 seconds. A) What is the angular displacement of the wheels in radians? 120 rad/s B) What is the angular acceleration of the wheels? 3.75 rad/s2 C) What is the final angular velocity of the wheels? 30 rad/s D) What is the final linear velocity of the wheels? 7.5 m/s 10) Suppose solid ball wheel with a mass of 4kg and a radius of 0.20 m rolls down a hill with an angular acceleration of 6.00 rad/s 2. A) What is the torque acting on the ball? N*m B) If the ball rolls for 10.0 seconds, what is its final linear velocity? 12 m/s 11) Calculate the net Torque exerted on the wheel shown below m R1 =.5m F1 = 25N, R2 =.33m, F2=30N 8

9 12) A 70 kg man and his 40 kg child are sitting on opposite ends of a see-saw that pivots on its center. The daughter sits 2.0m from the center. A) Draw a force diagram of the see saw with the people on it. B) How far from the center would the man have to sit for the see-saw to be in balance? 1.14 m 13) A torque of 7.5 N m must be exerted on a wheel in order for the wheel to have an angular acceleration of 15 rad/s 2. A) What is the moment of inertia of the wheel? 0.5 kg*m2 B) If the radius of the wheel is 0.30m, what is the force required? 25 N 14) A force of 400 N is applied to a 40 cm long socket wrench at an angle of 45 o with the handle. a) What is the Torque applied? 113 N*m b) What could be the maximum torque applied with the same force? 160 N*m Proton q=+1.6x10-19 C M= 1.67 x10-27 kg Electron q=-1.6x10-19 C M=9.11 x10-31 kg 15) What is the magnitude of the force a 8µC charge exerts on a 6µC charge 40 cm away? 2.7 N 16) Three identical point charges of 5.0 μc are placed on the x-axis. The first charge is at the origin, the second to the right at x = 0.20 m, and the third is at the 1.0 m mark. A) Draw a Force Diagram of each charge. B) What are the magnitude and direction of the electrostatic force which acts on the charge at the origin? (5.8 N) 17) A charge of -5.0 μc is placed on the x-axis at x = 0.20m. A second charge of +4.0 μc is placed at y = 0.30m. A) Draw the x y axis and label the charges on the axis B) What are the magnitude and direction of the electric field at the origin? 1.18*10 6 N/C, 19 o 18) A particle with a charge of 6.0 μc has a mass of kg. What electric field directed upward will exactly balance the weight of the particle? 3266 N/C 19) Determine the electric potential at a point in and Electric Field where an electron has an electrical potential energy of 2.0 * J? V 20) It takes 20 J of energy to move 5 C of charge from point A to point B. What is the potential difference between points A and B? 4V 9

10 21) A 6.0-V battery maintains the electrical potential difference between two parallel metal plates separated by 0.005m. What is the electric field between the plates? 1200 J/C 22) A proton, initially at rest, is accelerated through an electric potential difference of 150 V. a) What is the work done on the proton? 2.4*10-7 bonus) What is the speed of the proton? 1.69* ) A flashlight bulb draws 2.5 amps when connected to 9.0 volts. a) What is its resistance? 3.6 ohms b) What is the power dissipated? 22.5W 24) A 60 W light bulb uses 120 V of potential Difference. A) What is the current the bulb? 0.5A B) What is the resistance of the bulb? 240 ohms 25) Microwave is connected to a 110 V outlet and operates at a current of 9.0 A. It is used for 15 minutes a day for 30 days. A) How many kilowatt-hours of work is required to operate the microwave? 7.43 kwa B) What is the resistance of the circuit? 26) A R1 = 4.0 Ω, R2 = 8.0 Ω and R3 = 12.0 Ω are connected in parallel with a closed switch and a 12 V battery. A) Draw a schematic diagram of circuit. B) What is the equivalent resistance of the circuit. 2.18A C) What is the total current of the circuit? 5.50A D) What is the current through each resistor? 3A, 1.5A, 1A 27) A R1 = 6.0 Ω, R2 = 8.0 Ω and R3 = 10.0 Ω are connected in series with a closed switch and a 9 V battery. A) Draw a schematic diagram of circuit. B) What is the equivalent resistance of the circuit? 24 ohms C) What is the total current of the circuit? 0.375A D) What is the potential across each resistor? 2.25V, 3V, 3.75A 10

11 28) Use the diagram to answer the following questions. A) What is the equivalent resistance of the circuit? B) What is the total current of the circuit? 1.16 A C) What is the Potential Difference across each resistor? 3.48V, 4.64V, 3.86V D) What is the Current in each resistor? 1.16A, 1.16A,.386A E) What is the power of a resistor 10 Ohm? 1.49W 29) Use the diagram to answer the following questions. A) What is the equivalent resistance of the circuit? ohms B) What is the total current of the circuit? 1.6 A C) What is the power of a resistor 5 Ohm? 1.8 W 30) A microwave has a speed of 3.00*10 8 m/s and a wavelength of 3.50 cm. A) What is its frequency? 8.57*10^9 B) What is its period? 1.16*10^-10 11

12 31) The figure below is a "snapshot" of a wave at a given time. A) What is the frequency? 50 Hz B) What is the amplitude? 0.40 m C) What is the wavelength? 0.01 m D) What is the velocity of the wave? 20 m/s 32) The frequency of a tuning fork is 341Hz. What is the wavelength it produces? m/s 34) Standing on the sidewalk, you hear police siren that has a frequency of 950 Hz. It is moving towards you at 30 m/s. { f = f(v+v obs)/(v-v s) } A) What is the new frequency? 1041 Hz b) What is the frequency after it passes you? 874 Hz 35) A sound wave has a frequency of 256 Hz, and a wavelength of 1.30m. A) What is the speed of sound at this location? m/s B) The sound wave echoes off a canyon wall 4.0 km way, how long will it take to hear the echo? 24s 36) What is the speed of sound in a room if a resonance occurs in a CLOSED pipe with a length of 17.0 cm and a frequency of 512 Hz? 348 m/s 37) The speed of Light in a specific material is 2.10 * 10 8 m/s. What is the index of refraction? ) Light leaves a piece of crown glass into air at an incident angle of 18 o. What is the angle at which the light refracts? (n(glass) = 1.8) 33.7 degrees 39) If light from air is incident on liquid at and angle of 30 o and is refracted at an angle of 15 degrees, What is the index of refraction?