Physics Honors. Final Exam Review Free Response Problems

Transcription

1 Physics Honors inl Exm Review ree Response Problems m t m h 1. A 40 kg mss is pulled cross frictionless tble by string which goes over the pulley nd is connected to 20 kg mss.. Drw free body digrm, indicting ll forces in pproximte scle, for the mss on the tble. Show the direction of its ccelertion next to the free body digrm. b. Drw free body digrm, indicting ll forces in pproximte scle, for the mss tht is hnging from the string. Show the direction of ccelertion next to the free body digrm. c. Apply Newton s Second Lw to the mss on the tble to write n eqution for the TENSION. d. Apply Newton s Second Lw to the hnging mss to write n eqution for the TENSION of the hnging mss. e. Combine your equtions from c nd d to solve for the ccelertion. f. Solve for the tension in the string.

2 M 1 M 2 2. Two blocks, with msses M 1 = 0.25 kg nd M 2 = 0.35 kg, re connected by string nd lie on frictionless tbletop. A force = 3.6 N is pplied to block M 2.. Drw free-body digrm, indicting ll forces in pproximte scle, for M 1. b. Drw free-body digrm, indicting ll forces in pproximte scle, for M 2. c. Use Newton s Second Lw to write n eqution for M 1 d. Use Newton s Second Lw to write n eqution for M 2. e. Use equtions from c nd d to find the ccelertion of ech of the blocks. f. Use equtions from c nd d to find the tension force in the string.

3 3. A 100 kg object begins t rest on frictionless surfce. It then experiences 10 N force for 6.0 s.. Wht is its ccelertion during tht 6.0s? b. How fr does it trvel during tht 6.0s? c. Wht is its velocity fter tht 6.0s? The force is then turned off for the next 10s (no force cts on the object during this time). d. Wht is its velocity fter tht 10s time intervl hs elpsed? e. How fr does the object trvel during tht 10s? An opposing force 3.6 N is then used to stop the object over distnce of 5m. f. Wht ccelertion does the object experience while it trvels tht 5m? g. How much work is done by tht force s the object trvels its lst 5m?

4 4. A 250 kg object begins t rest on frictionless surfce. It then experiences 35.5 N force for 12.0 s.. Wht is its ccelertion during tht 12.0s? b. How fr does it trvel during tht 12.0s? c. Wht is its velocity fter tht 12.0s? The force is then turned off for the next 10s (no force cts on the object during this time). d. Wht is its velocity fter tht 10s time intervl hs elpsed? e. How fr does the object trvel during tht 10s? An opposing force of 72.6 N is then used to stop the object over distnce of 5m. f. Wht ccelertion does the object experience while it trvels tht 5m? g. How much work is done by tht force s the object trvels its lst 5m?

5 5. A 5.0 kg object is ttched to the end of string. It is swung in verticl circle whose rdius is 2.0m. At the top of the circle (its highest point) its velocity is 3.0 m/s.. On the digrm indicte the velocity nd ccelertion of the object t its lowest point. (use the circle on the left) b. On the digrm indicte the velocity nd ccelertion of the object t its highest point. (use the circle on the left) c. Drw free body digrm, indicting ll forces in pproximte scle, for the object t its highest point. Show the direction of its ccelertion next to the free body digrm. (use the circle on the right) d. Drw free body digrm, indicting ll forces in pproximte scle, for the object t its lowest point. Show the direction of its ccelertion next to the free body digrm. (use the circle on the right) e. Use Newton s Second Lw to write n eqution for the tension in the string when the object is t its highest point. f. Use conservtion of energy to determine the velocity of the object t its lowest point.

6 6. A roller coster ride t n musement prk lifts cr of mss 700 kg to point A t height of 90 m bove the lowest point on the trck, s shown bove. The cr strts from rest t point A, rolls with negligible friction down the incline nd follows the trck round loop of rdius of 20 m. Point B, the highest point on the loop, is t height of 50 m bove the lowest point on the trck.. Indicte on the figure the point P t which the mximum speed of the cr is ttined. b. Use conservtion of energy to clculte the mximum speed of the cr t this point P. c. Use conservtion of energy to clculte the speed of the cr t point B. d. Drw free-body digrm, indicting ll forces in pproximte scle, for the cr t point B. (the roller coster cr follows the inner side of the loop). e. Use Newton s Second Lw to determine the Norml orce pplied on the cr t point B. f. Now suppose tht friction is not negligible. How does it chnge the speed of the cr t point B?

7 7. A designer is working on new roller coster, nd she begins by mking scle model. On this model, cr of totl mss 0.5 kg moves with negligible friction long the trck show bove. The cr is given n initil speed v 0 = 1.5 m/s t the top of the first hill of height 2.0 m. Point A is locted t height of 1.9 m t the top of the second hill, the upper prt of which is circulr rc of rdius 0.95 m.. Clculte the initil kinetic energy of the cr t the top of the first hill. b. Clculte the potentil energy of the cr t the top of the first hill. c. Clculte the potentil energy of the cr t the top of the second hill. d. Use conservtion of energy to find the kinetic energy of the cr t the top of the second hill. e. Clculte the speed of the cr t the top of the second hill. f. Drw free-body digrm, indicting ll forces in pproximte scle, for the cr t the top of the second hill. g. Use Newton s Second Lw to find the norml force of trck on the cr t the top of the second hill. h. Now suppose tht friction force is not negligible. How does it chnge the speed of the cr t the top of the second hill?

8 8. The digrm bove shows bllistic pendulum. A kg bullet is fired into the suspended 2.5 kg block of wood nd remins embedded inside it ( perfectly inelstic collision). After the impct of the bullet, the block swings up to mximum height h. If the initil speed of the bullet ws 40 m/s:. Wht ws the momentum of the bullet before the collision? b. Wht ws the kinetic energy of the bullet before the collision? c. Wht ws the velocity of the bullet-block system just fter the collision? d. Wht ws the totl kinetic energy of the bullet-block system fter the collision? e. Wht is the mximum possible potentil energy of the bullet-block system when it reches its mximum height? f. Wht is the mximum possible height of the bullet-block system?

9 9. In the circuit shown bove, X, Y. nd Z represent three light bulbs, ech rted t 60 wtts, 120 volts. Assume tht the resistnces of the bulbs re constnt nd do not depend on the current.. Wht is the resistnce of ech bulb? b. Wht is the equivlent resistnce of the three light bulbs when rrnged s shown? c. Wht is the totl power dissiption of this combintion when connected to 120-volt source s shown? d. Wht is the current in bulb X? e. Wht is the potentil difference cross bulb X? f. Wht is the potentil difference cross bulb Z?

10 10. The circuit shown bove includes 72 V bttery nd four resistors. ind the following:. the totl resistnce of the circuit b. the current in the bttery c. the current in the 10-ohm resistor d. the potentil difference cross the 10-ohm resistor

11 Physics Honors R inl Exm Review Answers 1.. b m h g c. T = m t d. T m h g = m h e. = 3.3 m/s 2 f. T = N b. m 1 g m T M 2 b. v c. T = m 1 d. T = m 2 e. = 6 m/s 2 f. T = 1.5 N 3.. =.1 m/s 2 b. x = 1.8 m c. v =.6 m/s d. v =.6 m/s e. x = 6 m f. = m/s 2 g. W = -18 J 4.. = m/s 2 b. x = 10.2 m c. v = 1.7 m/s d. v = 1.7 m/s e. x = 17 m f. = m/s 2 g. W = -363 J c. T m g T v. d. mg e. T + mg = mv 2 /r f. v L = 9.3 m/s

12 6.. At the bottom of the slope. P b. v = 42 m/s c. v =28 m/s d. N mg e. N = 20, 580 N f. riction would decrese the speed t point B. 7.. KE = 0.56 J b. GPE = 9.8 J c. GPE = 9.3 J d. KE = 1.06 J e. v = 2.06 m/s f. mg g. N = 2.7 N k. riction would decrese the speed t point A. 8.. p =.8 kgm/s b. KE O = 16 J c. v =.32 m/s d. KE =.13 J e. E =.13 J f. h = m Ω b. 360Ω c. 40W d. 0.33A

13 e. 79.2V f. 40.8V Ω b. 8A c. 2A d. 20V