LAHS Physics 2004-2005
End-of-Year
Final Review Problems
Your End-of-Year Physics Final covers the ENTIRE YEAR'S material in Physics. It has TWO parts to be taken on the day of the Senior Final. You will have 90 minutes to complete the following:
Part I - 2 Free Response Questions to be completed individually
Part II - 25 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 => 10% of grade
Semester 2 Final – Part II => 10% of grade
Part I - 2 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 17 Free Response Review Problems in this packet, a set of 5 will be announced by Monday June 6th for you to prepare perfect solutions of which ONE of the announced 5 will be randomly chosen to be submitted on the day of the Final. Then for the remaining minutes during the Final, you will be asked to INDIVIDUALLY solve ONE of the remaining UNANNOUNCED 12 problems in class.
Part II - 25 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 will distributed via the class website. You will be assigned to a partner on the day of the Final. Then you and your assigned partner will have 60 minutes maximum for this part to complete. If you and/or your partner finishes this part early, you may continue on to the Free Response part (you or your partner may continue, if needed, with the MC part for the maximum of 60 minutes)
The Free Response problems on the exam will be graded with partial credit. 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. A 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
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?
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
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 Ω resistor. Determine what the voltmeter would read for this circuit.
E. Determine the voltage across the 30 and 10 Ω resistors.
F. Determine the voltage across the combination of the 15, 20 and 40 Ω resistors.
G. Determine the current through the 40 Ω 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. 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?
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