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LAHS Physics 2005-2006 End-of-Year

Final Review Problems Your End-of-Year Physics Final covers the ENTIRE YEAR'S material in Physics. Juniors and Seniors will take Finals on the SAME Senior Final day so no-one has more of an advantage. The Final has TWO parts. You will have 90 minutes to complete the following: Part I - Free Response Questions to be completed individually Part II - Multiple Choice Questions to be completed in an assigned pair Your Semester grade will be calculated as follows: Quarter 3 grade => 40% of grade

Quarter 4 grade => 40% of grade Semester 2 Final – Part I => 5% of grade

Semester 2 Final – Part II => 15% of grade Total =>100% It is highly recommend that you study/review in small groups well ahead of your scheduled Final, preferably with your assigned partner so that you can work out collaboration and cooperation details ahead of time. Sign-up in advance for tutoring help with your teacher or tutors at the Tutorial Center. If you happen to miss any part of the Final for any reason, expect to do the all of the make-up exam(s) ALONE. Part I - 1 Free Response Questions to be completed individually The purpose of this section is to assess your individual ability to be a SELF DIRECTED LEARNER, a RESPONSIBLE INDIVIDUAL and your ability to demonstrate your CRITICAL THINKING SKILLS. Of the Free Response Review Problems in this packet, a set of 6 will be announced on the class website on Friday June 2nd for you to prepare perfect solutions. On the day of your final, you will be asked to submit this ONE randomly chosen problem from the 6 previously announced problems. This ONE problem will count for 5% of your Semester 2 Grade. You will not be solving a Free Response problem in class on the day of your Final. The Free Response problem on the exam will be graded with partial credit because the process of Problem Solving is important for anything in life and we want to know if you can demonstrate that process clearly. Point distributions within a particular problem will depend on the difficulty and concepts used to solve the problem. Generally, points will be awarded for the following:

1. clear diagram (if not given) or free body diagram with all given data indicated 2. writing the correct equation(s) to be used in solution 3. correct mathematical manipulations and algebraic substitutions (if necessary) 4. a clearly indicated correct answer with correct units 5. a complete sentence explaining your resultant numerical answer

Part II - Multiple Choice Questions to be completed in an assigned pair The purpose of this section is to assess your PHYSICS KNOWLEDGE and your ability to WORK COLLABORATIVELY and EFFECTIVELY COMMUNICATE your PROBLEM SOLVING SKILLS. The questions are mostly conceptual, some mathematical with the purpose of assessing how well you understand the concepts discussed throughout the year – similar to the Practice Multiple Choice questions distributed via the class website. Some of the MC questions will come directly from all of the Free Response review packet problems with different variable values. You’ll have to work out the problems and choose the best answer from the Multiple Choice answers. Approximately 40-50 Multiple Choice questions will be on the Final Exam. You will be assigned to a partner on the day of the Final and you may choose to work together or separately. Then you and your assigned partner will have 90 minutes maximum for this part to complete. This part will count for 15% of your Semester 2 Grade.

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Free Response Review Questions 1. Alice Springs, an Olympic long jumper, accelerates towards jump zone during a practice run in

Seoul, Korea. She jumps with an initial velocity of 7.2 m/s at and angle of 48o above the horizontal. Alice lands at the same height she started.

A. Predict the long jumpers total time in flight? B. Predict the maximum height the long jumper reaches? C. Predict the range of the long jumper? D. Predict the long jumper’s velocity at the apex? E. Predict the acceleration of the long jumper 0.05 s before the apex? F. Predict the final velocity of the long jumper just before hitting the pad? G. Draw Displacement, Velocity and Acceleration graphs of her 2D motion. 2. Dawn falls out of a window 4.0 m above the ground. She lands on her back on soft soil so that she

decelerates to rest through a distance of 10 cm. Assume the deceleration is constant. If her mass is 60 kg:

A. Predict the average force exerted on her body by the soil. B. Does the average force exerted on Dawn’s body increase, decrease or stay the same if the

soft soil is replaced by hard concrete? Explain your answer.

3. A block of mass m1 = 5.2kg sits on a frictionless, horizontal surface and is connected to a second mass m2 by a light string over a frictionless, massless pulley. If the acceleration of the system is 2.8 m/s2 :

A. Predict the mass of m2. B. Sketch a graph of Acceleration vs. Time for the system. 4. The Los Altos High School Freshman, Sophomore, Junior and Senior classes are participating in

a two dimensional tug-o-war. The Freshman class pulls with 680 N @ 20°. The Sophomore class pulls with 980 N @ 90°. The Junior class pulls with 1250 N @ 190°. Predict the force the Senior class should pull with to bring all the “tugs” into equilibrium?

5. A 65 kg man with an initial velocity of 20 m/s slides up a 38° frictionless inclined plane. Predict

where the man land as measured from the vertical edge of the ramp?

θ

Vo 6 m

Range

m2

m1

3

6. Consider a 100 kg professional wrestler sliding, from rest, down a steep San Franciscan street, 42 m long. The street is inclined at 38° with respect to the horizontal and is covered in thick oil resulting in a coefficient of kinetic friction of 0.42. At the bottom of the street a telephone cable hangs vertically from 26 meters directly above. If the wrestler grabs onto the cable at the bottom of the hill, predict the highest she will swing?

7. CalTrans and the California Highway Patrol have hired you to design a freeway off ramp. To

ensure drivers aren’t speeding, one section of the ramp is designed to be frictionless, bank 30° and turn a quarter circle of radius 80m.

a. Calculate the exact speed a car must start around this section of track in order to safely make the turn.

b. What are two different design changes that would increase the safe speed of a similar section of off ramp?

8. Predict the mass of the Earth given that the Moon’s orbital radius is 3.84 x 108 meters and its

orbital period is 27.3 days. 9. A bicycle racer pedals from rest to 24 m/s in 12.4 seconds. The racer and the bike have a

combined mass of 88 kg. Predict work done by the racer and the power output of the racer during the 12.4-second sprint.

10. A medical relief airplane climbs to an altitude of 200 m and flies at a constant cruising velocity of

80 m/s. The copilot steps to the back of the plane and opens the cargo door. She wants to drop a medical supply package to a landing site at a remote village.

i) Neglecting air resistance, use 2-D kinematics to determine how far (horizontally) before the plane flies over the village must the package be dropped?

ii) To prevent the 15 kg supply package from getting damaged, the villagers set up an airbag at the landing site. The airbag is capable of stopping the supply package in 0.4 s and stands 5 meters above the ground. Use conservation of energy to determine the final velocity of the package just before it hits the airbag and determine the average force, by using the impulse–momentum theorem, imparted to the supply package by the airbag?

11. General Wave questions

26 m

200 m

Range

Airbag

4

6 ? 4 ?

10 V

A. Draw 3 complete cycles of a wave with frequency 60 Hz with an amplitude of 4 m. B. What is the amplitude of a wave that is half as loud as the wave you have drawn above? C. What is the period of a wave that is three times the frequency as the wave you have drawn

above? D. Would you be able to hear a wave that has half the frequency you drew above? Why or why

not? E. If you were asked to make an closed piped wind instrument with its resonating fundamental

frequency of 60 Hz, how long would the pipe have to be? F. If an open pipe had a length of 1.2 meters, what would be the wavelength of the

fundamental frequency? 12. Suppose that electrical attraction, rather than gravity were responsible for holding the Earth in

orbit around the Sun. If equal and opposite charges Q were placed on the Earth and the Sun, what should be the value of Q be to maintain the present orbit? (Hint: treat the Earth and Sun as point charges.)

13. Suppose you plugged into the wall outlet a configuration of electric appliances as represented by

the resistors in the circuit diagram shown below.

A. Find the equivalent total resistance of the circuit shown below.

B. In the circuit diagram above, draw in an ammeter to measure the current from the battery. C. Determine what the ammeter would read for this circuit. D. In the circuit diagram above, draw in a voltmeter to measure the voltage across the 15 ?

resistor. Determine what the voltmeter would read for this circuit. E. Determine the voltage across the 30 and 10 ? resistors. F. Determine the voltage across the combination of the 15, 20 and 40 ? resistors. G. Determine the current through the 40 ? resistor. H. How much power is dissipated by all the resistors in the circuit shown above? I. How much power is supplied by the power source in the circuit shown above?

14. Robert wants to build a stun gun to shock his sister. He knows that any more than 20 milliamps of

current can cause permanent physical damage to human beings. If Robert uses the household power outlet (120 Volts @ 15 Amps) and a transformer with 50 primary turns, how many secondary turns does the transformer need and what is the secondary voltage if he wants to shock his sister with 20 milliamps?

15 ?

30 ?

40 ? 20 ?

10 ?

5

15. Under the floor of your physics room there are 10,000 coils of current carrying wire wrapped around the perimeter of the room. Placed interior to the coils, an iron sheet used to magnetify (the magnification of the magnetic field) B field to strength of 0.061 Tesla pointing straight up towards the ceiling. Mr. Florendo wants to walk across the room with a 1-meter conducting bar and induce an EMF. Which way does the bar have to be oriented to induce an EMF? Mr. Florendo’s radio needs 12 volts of electric potential to operate his radio. If he hooks the radio up to the bar, how fast does he have to walk across the room to make it work?

16. Several questions about EM Induction.

A. Explain what is electromagnetic induction. How and what is produced with EM Induction? What are 3 applications of EM Induction?

B. Describe the similarities and differences between a simple electric motor and an electric generator.

C. In detail, describe a transformer, its purpose, how it achieves its purpose, and its applications.

D. Suppose you needed a 40-volt source but had no power source other than the wall outlet which has voltage of 120 V. You do, however, have materials available to make a transformer. E. Describe and draw a picture of the transformer you would build to transform the wall outlet 120 V to the needed 40 volts.

F. Suppose you are successful in constructing your transformer. You connect the primary coil to the 120 V power source and connect its secondary coil to a small motor. If your motor dissipates 20 Joules of energy every second, what is its resistance?

G. How much current is flowing through the secondary coil? 17. A coil of wire has current flowing through it. A second coil is moved away from the first coil. Loop 1 Loop 2 a) What is the direction of the current in loop 1? CW or CCW

b) Why does an induced current flow in loop 2? c) What is direction of the induced current in loop 2? CW or CCW Explain in detail or indicate in the picture above how you determine your answer. d) What are at least 3 ways you could increase the current in loop 2? e) Where does the energy come from to make the current flow in loop 2?

v

External force pushes loop 2 to the left

+ -

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18. In the figure below, the central particle with charge q = -1 µC is surrounded by two circular rings of radii 1.5 cm and 2 cm containing stationary charged particles,.

a) What’s the magnitude of the NET electrostatic force on the central particle due to the other particles?

b) What’s the direction of the NET electrostatic force on the central particle due to the other

particles? c) If the mass of the central particle is the mass of an electron, calculate the initial acceleration

of the particle due to the net electrostatic force. 19. Draw all your ray diagrams for the following problem on the sheet with the following lens and

object configurations already printed on it.

A. Shown below is a concave mirror with an object. Correctly draw the image formed by the mirror.

+4q

-2q -2q +2q

+2q

+q

-7q

+q

-2q -2q

Virtual or Real? _______________

C

Object

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B. Shown below is converging lens. Correctly draw the image formed by the lens.

C. Shown below is diverging lens. Correctly draw the image formed by the lens.

20. One method of determining the refractive index of a transparent solid is to measure the critical

angle θc when the solid is in air.

A. If θc = 40.2° for this material, what happens to light if it is incident at 41° to the normal? B. If θc = 40.2° for this material, what is the index of refraction of the solid? C. For light that is incident at 38° to the normal, what is the speed of light in this solid?

Object f f

Virtual or Real? _______________

Virtual or Real? _______________

f f

Object