METU D. F. HIGH SCHOOL 2017-2018 ACADEMIC YEAR, 1 st SEMESTER GRADE 11 / PHYSICS REVIEW FOR GENERAL EXAM-3 UNIFORMLY ACCELERATED MOTION IN TWO DIMENSIONS, ENERGY, IMPULSE & MOMENTUM & TORQUE DECEMBER 2017 Name & Surname:... No:... Class: 11 /... 1. An object is thrown horizontally with a speed of v from point M and hits point E on the vertical wall after t seconds as shown in the figure. (Ignore air friction.) 3. An object is thrown horizontally from point S with an initial speed of v and its hits point P on the wall. All the friction forces are ignored. The points on the wall are equally spaced. If the gravitational acceleration was smaller, how would h and t change? h : _ If the object were thrown horizontally with the same initial speed from point T, where would it hit on the wall? Prove your answer with calculations. t : _ 2. Two objects M and S are thrown as shown in the figure. The times of flights of the objects are the same. (Ignore air friction.) 4. Objects X and Y are thrown with the same initial speeds as shown in the figure. (Figure is composed of identical squares and air friction is ignored.) Read the following statements. If the statement is CORRECT print "C", or if it is WRONG then print "W". You have to correct the wrong statements by using an appropriate word(s) or phrase(s). The height h 1 is one-fourth of the height h 2. At which point object Y is, when object X is at point N? Prove your answer by calculations. The change in velocity of object M is equal to the change in velocity of object S. The speed of object M when it hits the ground is equal to the speed of object S when it hits the ground. 1
5. A plane flies horizontally with a constant speed at an altitude of h when a package is released from the plane. (Ignore friction.) Read the following statements. If the statement is CORRECT print "C", or if it is WRONG then print "W". You have to correct the wrong statements by using an appropriate word(s) or phrase(s). 7. Object X is thrown obliquely form the ground with an initial speed of v. After a while object Y is thrown vertically upward with the same initial speed. They collide at point O which is the maximum height reached by object X. (Ignore friction and sin37 o =0,6.) The package is freely falling with respect to the pilot of the plane. The package is thrown horizontally with respect to an observer on the ground. What is the speed of object Y at point O in terms of v? The velocity of the package is constant with respect to the pilot of the plane. 6. An object is thrown obliquely from the ground and it follows the path as shown in the figure. h max is the maximum height reached by the object. (Ignore air friction.) 8. Objects X, Y and Z are thrown obliquely with speeds of v 1, v 2 and v 3 as shown in the figure. (Ignore friction. The figure is composed of identical squares.) What is the ratio of h to h max? Read the following statements. If the statement is CORRECT print "C", or if it is WRONG then print "W". You have to correct the wrong statements by using an appropriate word(s) or phrase(s). 2 The range of object X is equal to the range of object Z. The maximum height reached by object X is equal to the maximum height of object Y. The time of flight of object X is equal to the time of flight of object Z.
9. An object is fired from point K with an initial kinetic energy of 30 J. It can reach point L, slides down and its kinetic energy is 14 J at point K. The surface of the inclined plane has a constant friction. (sin37 o =0,6; sin37 o =0,8 ) 11. The masses of objects K and L are 4m and m respectively. The system given in the figure is released. The pulley is frictionless and supposed to be weightless. Read the following statements. If the statement is ABSOLUTELY CORRECT print "A", if it is POSSIBLE print "P" or if it is WRONG then print "W". You have to correct the wrong statements by using an appropriate word(s) or phrase(s). What is the maximum height reached by object L from its initial position in terms of h? The potential energy of the object with respect to the ground is 16 J. The work done by friction force between points K and L is -8 J. The magnitude of the friction force on the surface of the inclined plane is 10 N. 10. 6 kg and 4 kg objects are connected by an elastic spring and they are applied a vertical force of 60 N as shown in the figure. The spring constant of the spring is 72 N/m. Friction and the mass of the spring are ignored. (g=10 N/kg) 12. Objects X and Y have masses of 4 kg and 1 kg respectively. They are tied by a massless rope as shown in the figure. When the system is released, object X starts to move downward and hits point C on the horizontal surface while object Y starts to move from point A to point B. The weight of the pulley and all the friction forces are ignored. (g=10 N/kg, sin30 o =0,5 and sin37 o =0,6) What is the maximum elastic potential energy of the spring in J? What is the speed of object Y at point B in m/s? 3
13. A 0,5-kg mass is attached to one end of a spring and the other end is tied to a wall. The spring-mass system is pulled and released on a frictionless horizontal surface. The energy (potential & kinetic) versus displacement graph of spring-mass system is given. 15. The magnitude of the net force versus displacement graph of an object that is initially at rest on a horizontal surface is given. Plot kinetic energy versus displacement graph of the object. a) What is the maximum speed of the mass in m/s? b) What is the maximum compression of the spring in cm? 14. The mass of object K is 3m and the mass of object L is m. When the system given in the figure is released, the elastic spring compresses by an amount of x. (Friction forces, the weight of the pulley and the weight of the spring are ignored.) 16. A 2 kg object is released from the position as shown in the figure. The length of the rope is 1 m and the spring constant of the elastic spring is 1000 N/m. (g=10 N/kg, the mass of the rope is ignored.) What is the maximum compression of the spring in cm? What is the maximum elastic potential energy stored in the spring in terms of mgx? 4
17. The masses of objects K and L are 2 kg and 1 kg respectively. They are moving toward each other with constant speed of 10 m/s and 5 m/s on a frictionless horizontal surface as shown in the figure. They collide and stick. 19. The masses of object X and Y are m and 2m respectively. Object X moves with a constant speed of 2v on a frictionless horizontal surface. It collides object Y that is stationary on the horizontal surface as in Figure-1. After collision, object X moves with a constant speed of v and object Y can reach at a height of 2h as in Figure-2. ( g is the gravitational acceleration.) What is the velocity of the combined mass in m/s? What is the speed of object X (v) after collision in terms of g and h? 18. The masses of object K and L are m K and m L respectively. Object K is released from point A. It moves downward on the frictionless path and collides object B that is stationary at point B and stick. The combined mass can merely reach point C. 20. The masses of object K and L are m K and m L respectively. They are moving with constant velocities of +15 m/s and +10 m/s on a frictionless horizontal surface as shown in the figure. K collides L elastically and its velocity after the collision is +10 m/s. What is the ratio of m K to m L? What is the ratio of m K to m L? 5
21. The masses of object K and L are 8 kg and 4 kg respectively. They are placed at the two sides of an elastic spring that has spring constant of 2400 N/m. Then the spring is compressed by 1 m and objects are tied by a rope as shown in the figure. (The horizontal surface is frictionless and the mass of the spring is ignored.) 23. A bullet of mass m moving horizontally at a constant speed of 2v hits a stationary wooden block of mass 20m as in Figure-1. The bullet penetrates the wooden block and leaves with a constant speed of v as in Figure-2. (The horizontal surface is frictionless. The loss of mass during penetration is ignored. ) If the rope were cut, what would be the velocities of the objects (in m/s) after they leave the spring? What is the impulse imparted by the wooden block on the bullet in terms of mv? 22. The masses of object K and L are 2 kg and 3 kg respectively. They are moving with constant velocities of +20 m/s and +10 m/s on a frictionless horizontal surface as shown in the figure. They collide and stick. 24. A wooden block of mass "2m" is tied to the end of a 2 m long rope and released as shown in the figure. While the wooden block passes from point A, a bullet of mass "m" hits the block with a speed of "2v" and embeds. (Ignore air friction, g=10 N/kg, sin53 o =0,8 and cos53 o =0,6.) What is the amount of energy lost during collision in J? If the wooden block had stopped after the bullet had embedded, what was the initial speed (2v) of the bullet in m/s? 6
25. A force of magnitude of "F" is applied as shown in the figure. The torque with respect to point X is "- 3 N.m". (Figure is composed of identical squares.) 27. A plate is hinged at point O on a frictionless horizontal surface. Four forces are applied on the plate as shown in the figure. (Figure is composed of identical squares and each side of the squares is "d" for distance and "F" for forces calculations.) What are the torques with respect to point Y and Z in N.m? What is the net torque with respect to point O in terms of "F.d"? 26. Three forces are applied as shown in the figure. The magnitude of the net torque with respect to point K is "τ K " and the magnitude of the net torque with respect to point L is "τ L ". (Figure is composed of identical squares and each side of the squares is "d" for distance and "F" for forces calculations.) 28. A uniform plate is hinged at point O on a horizontal frictionless surface. Four forces having magnitudes of F, 2F, 3F and 4F are applied on the plate as shown in the figure. What is the net torque with respect to point O in terms of "F.r"? What is the ratio of "τ K " to "τ L "? 7
29. A rod is hinged at point O on a horizontal fricitionless surface. Four forces are applied on the rod. Three of them are given in the figure. Their magnitudes are F, 2F and 3F. (The rod is composed of identical divisions.) 31. A rod is hinged at point O on a horizontal fricitionless surface. Four forces having magnitudes of 2F, 2F, and 5F are applied on the rod as shown in the figure. The torque applied by force having magnitude of 2F with respect to point O is "- 8 N.m". (The rod is composed of identical divisions and sin37 o =0,6; cos37 o =0,8) If the net torque with respect to point O is zero, what are the magnitude (in terms of F) and the direction (up or down) of the fourth force that is applied perpendicular the rod at point A? What is the net torque with respect to point O in N.m? 30. A rod is hinged at point O on a horizontal fricitionless surface. Four forces having magnitudes of F, 3F, 3F and 4 3F are applied on the rod as shown in the figure. (The rod is composed of identical divisions and the length of each division is "d".) 32. A plate is hinged at point O on a horizontal fricitionless surface. Three forces having magnitudes of F 1, F 2 and F 3 are applied on the plate as shown in the figure. The magnitudes of the torques applied by the these forces with respect to point O are equal. (Plate is composed of identical squares.) What is the net torque with respect to point O in terms of "F.d"? What is the decreasing order among the magnitudes of these forces? (sin30 o =1/2, cos30 o = 3 / 2 ) 8