Unit 6 actice Test 1. Which one of the following gaphs best epesents the aiation of the kinetic enegy, KE, and of the gaitational potential enegy, GE, of an obiting satellite with its distance fom the cente of the Eath? A. Enegy KE B. Enegy KE GE GE C. Enegy KE D. Enegy GE GE KE. A point mass is moing in a hoizontal cicle with a elocity of constant magnitude. At one paticula time, the mass is at. A shot time late, the mass is at Q, as shown below. Q Which ecto diagam coectly shows the change in elocity Δ of the mass duing this time? A. B. C. D. 1
3. A satellite of mass m and speed obits the Eath at a distance fom the cente of the Eath. The gaitational field stength due to the Eath at the satellite is equal to A.. B.. C. m m. D.. 4. A paticle is moing in a cicle with unifom speed. Which one of the following diagams coectly shows the diection of the acceleation a and elocity of the paticle at one instant of time? A. a B. a C. D. a a 5. A bick is placed on the suface of a flat hoizontal disc as shown in the diagam below. The disc is otating at constant speed about a etical axis though its cente. The bick does not moe elatie to the disc. Which of the diagams below coectly epesents the hoizontal foce o foces acting on the bick?
6. oints and Q ae at distances R and R espectiely fom the cente X of a disc, as shown below. R Q Linea speed Centipetal acceleation A. a R X B. a C. a D. 4a The disc is otating about an axis though X, nomal to the plane of the disc. oint has linea speed and centipetal acceleation a. Which one of the following is coect fo point Q? 7. The centipetal foce F acting on a paticle of mass m that is taelling with linea speed along the ac of a cicle of adius is gien by A. F =. m B. F = m. C. F = m m. D. F =. 8. Which of the following expessions coectly elates the adius R of the cicula obit of a planet ound a sta to the peiod T of the obit? A. R 3 T 1 B. 3 R T C. R T 3 1 D. R T3 9. The centipetal foce that causes a ca to go ound a bend in the oad is poided by A. the foce poduced by the ca engine acting on the wheels. B. the fiction between the tyes and the oad. C. the weight of the ca. D. the foce exeted by the die on the steeing wheel. 3
1. Two satellites of equal mass, S 1 and S, obit the Eath. S 1 is obiting at a distance fom the Eath s cente at speed. S obits at a distance fom the Eath s cente at speed atio of the centipetal foce on S 1 to the centipetal foce on S is. The A. 1 1. B.. C. 4. D. 8. 8 4 11. A satellite obits the Eath at constant speed as shown below. satellite Eath (a) Daw on the diagam (i) an aow labelled F to show the diection of the gaitational foce of the Eath on the satellite. an aow labelled V to show the diection of the elocity of the satellite. () (b) Although the speed of the satellite is constant, it is acceleating. Explain why it is acceleating. () (c) Discuss whethe o not the gaitational foce does wok on the satellite. (Total 7 maks) 4
1. This question is about linea and cicula motion. A ca moes along a staight oad. At time t = the ca stats to moe fom est and oil begins to dip fom the engine of the ca. One dop of oil is poduced eey.8 s. Oil dops ae left on the oad. The position of the oil dops ae dawn to scale on the gid below such that 1. cm epesents 4. m. The gid stats at time t =. diection of motion 1.cm (a) (i) State the featue of the diagam aboe which indicates that, initially, the ca is acceleating. On the gid aboe, daw futhe dots to show whee oil would hae dipped if the dops had been poduced fom the time when the ca had stated to moe. () (iii) Detemine the distance moed by the ca duing the fist 5.6 s of its motion. (b) Using infomation fom the gid aboe, detemine fo the ca, (i) the final constant speed. () the initial acceleation. 5
() (c) The ca then tuns a cone at constant speed. assenges in the ca who wee sitting upight feel as if thei uppe bodies ae being thown outwads. (i) Identify the foce acting on the ca, and its line of action, that enables the ca to tun the cone. () Explain why the passenges feel as if they ae being thown outwads. (Total 13 maks) 13. This question is about the kinematics and dynamics of cicula motion. (a) A ca goes ound a cue in a oad at constant speed. Explain why, although its speed is constant, it is acceleating. () 6
In the diagam below, a mable (small glass sphee) olls down a tack, the bottom pat of which has been bent into a loop. The end A of the tack, fom which the mable is eleased, is at a height of.8 m aboe the gound. oint B is the lowest point and point C the highest point of the loop. The diamete of the loop is.35 m. A mable.8 m C.35 m gound B The mass of the mable is.5 kg. Fiction foces and any gain in kinetic enegy due to the otating of the mable can be ignoed. The acceleation due to gaity, g = 1 ms. Conside the mable when it is at point C. (b) (i) On the diagam opposite, daw an aow to show the diection of the esultant foce acting on the mable. State the names of the two foces acting on the mable. () (iii) Deduce that the speed of the mable is 3. ms 1. (i) Detemine the esultant foce acting on the mable and hence detemine the eaction foce of the tack on the mable. (4) (Total 1 maks) 7
14. This question is about cicula motion. A linea sping of negligible mass equies a foce of 18. N to cause its length to incease by 1. cm. A sphee of mass 75. g is attached to one end of the sping. The distance between the cente of the sphee M and the othe end of the unstetched sping is 5. cm, as shown below. M 5. cm The sphee is otated at constant speed in a hoizontal cicle with cente. The distance M inceases to 6.5 cm. (a) Explain why the sping inceases in length when the sphee is moing in a cicle. () (b) Detemine the speed of the sphee. (4) (Total 6 maks) 8
15. This question is about atomic models. The diagam below (not to scale) shows a simple model of the hydogen atom in which the electon obits the poton in a cicula path of adius R. electon chage e poton chage +e R (a) On the diagam, daw an aow to show the diection of (i) the acceleation of the electon (label this A); the elocity of the electon (label this V). (b) State an expession fo the magnitude of the electostatic foce F acting on the electon. (c) The obital speed of the electon is. 1 6 m s 1. Deduce that the adius R of the obit is 5. 1 11 m. (d) A moe complex model of the atom suggests that the obital adius can only take cetain discete alues. This leads to the idea of discete enegy leels within the atom. Outline the eidence that suppots the existence of discete enegy leels. (Total 9 maks) 9