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Phys.2211 practicing problems • Review the quizzes and tests. • Practice ‘stop to think’ Chapt. 12, 14, 16, 17, 20. (1,2,3) • Summarize the homework. • prepare your own formula sheet Final exam. schedule: MWF class Dec. 10, Friday 8:00 -10:30am MW class Dec. 13, Monday 4:15—6:45 pm comprehensive problems 1.You may use this way to get a bullet speed. Suppose a bullet of mass 8.00 g is fired into a block of mass 2.50 Kg initially at rest at the edge of a frictionless table of height 1.00m. The bullet remains in the block, and after impact the block lands a distance 2.00 m from the bottom of the table, Determine the initial speed of the bullet. (review perfectly inelastic collision and projectile motion. V(bullet) = 1388m/s) (2) A ball of mass m is attached to a string of length L. It is being swung in a vertical circle with enough speed so that the string remains taut throughout the ball's motion. (see Homework #7) • Find : • (1) Tb-Tt, the difference between the tension in the string at the bottom relative to that at the top of the circle in terms of m, g ( see your homework #7) • (2) find the centripetal acceleration difference at the bottom and the top 3.Three identical balls are thrown from the top of a building, all with the same initial speed the first is thrown horizontally, the second at some angle above the horizontal and third at some angle below the horizontal. Neglecting the air resistance, rank the speeds of the balls at the instant each hits the ground 4. See the problem 10.42, ( at homework #7) (1) If m and 2m stick together, after collision, what is the final velocity after collision? [+(1/3) sqrt(2gh)] . What is the percentage of kinetic energy lost after collision? (2/3 = 67%) (2) If the collision between the packages is elastic (i) what is the velocity of m? what is the velocity of 2m after collision? (ii) to what height does the package of mass m rebound? [1/9 (3m)=1/3m] (ii) What is the percentage of the total kinetic energy lost after collision? (0) 5 See the problem 12.71, (page 382 Homework #9), if we neglect the friction between m1 and table. The pulley mass is mp (i) what is the acceleration of the system? (ii) If m2 start h (meters) from the ground what is the speed when m2 hit the ground, (iii) you also can get that speed using work and energy equation. Please do it. 6. Santa Claus stands on the top of the hill, he is sending the Christmas gifts to you, a sphere, a cylinder, and circular hoop all of mass M and radius R. they are rolling down from rest at the same instant of time, which one has the greatest speed of center of mass? which one will get the bottom of the hill first? Why? • Please show the time for each one 7. Two equal masses are attached to identical ideal strings, length L, next to one another. One mass is pulled 10o and the other pulled only 5o , then release. The masses are released simultaneously. Which mass reaches the vertical position( θ = 0o) first? Explain your reasoning. 8. The figure shows a 2Kg mass riding on top of a 4Kg as it oscillates on a frictionless surface. The spring constant is 100N/m and the coefficient of static friction between the two blocks is 0.50. What is the angular frequency ω of the system? What is the maximum oscillation amplitude for which the upper block does not slip? 9. Homework 16.69 (homework # 11) The 50 kg circular lead piston shown in the figure floats on 0.490 mol of compressed air. The cylinder diameter is 10 cm. 1.What is the pressure of the air inside ( don’t forget atmosphere pressure) 2. If we heat the air without change the pressure, raise the temperature from 30 C to 200 C, how far does the piton move 3. how much heat Q is transferred ( Cp=29J/mol K) Q=nCpΔT 4. what is the change in thermal energy ΔE(th) = W + Q 10. ( Homework 17.59 #11) 0.10 of a monatomic gas follows the process shown in the figure, how much heat energy is transferred to or from the gas during the process 1→2? (244J) how much heat energy is transferred to or from the gas during the process 2→3? (406J) What is the work done during the process 2 →3? What is the total change of thermal energy of the gas