2017 PHYSICS FINAL REVIEW PACKET EXAM BREAKDOWN

Transcription

1 2017 PHYSICS FINAL REVIEW PACKET EXAM BREAKDOWN Topics: Forces Motion Momentum Gravity Electrostatics DATE: TIME: ROOM: PROCTOR: YOU ARE REQUIRED TO BRING: 1. CALCULATOR (YOUR OWN NO SHARING) 2. PENCIL WITH ERASER. YOU WILL BE GIVEN: 1. FORMULA SHEET 2. SCRAP PAPER 3. EXAM BOOKLETS Disclaimer: This material represents a general approximation of the types of problems that were engaged in during the first half of the year. That is, this should not be your only vehicle of review. THE FINAL IS NOT, I REPEAT, NOT LIMITED TO THE MATERIAL CONTAINED ON THESE PAGES.

2 1. Which will fall faster: a 10 kg ball or a 5.0 kg ball? Concept Questions: 2. What two quantities are needed to determine the acceleration of an object? 3. Compare (ball thrown upward): The time it takes for a ball to go up and down. The velocity of the ball going up and the velocity of the ball when it returns? 4. What is the difference between a scalar and vector quantity? 5. Which has more inertia: a 5.0 kg block or a 15.0 kg block? 6. If you triple the net force on an object, its acceleration will increase by what factor? 7. A person is hanging on a rope. If the rope is pulled upward, what will happen to the tension? 8. If the net force on an object is zero, what can be concluded about its motion?

3 9. A person throws a ball horizontally; at the same instant an identical ball is dropped from the same height. Which one hits the ground first? 10. What angle produces the maximum range? The maximum height? The longest time in air? 11. A horizontal force of 10.0 N is required to pull a cart at a constant speed. What is the friction force? 12. What quantity is zero when a projectile is at its maximum height? 13. What are the units for: distance, velocity, acceleration, force, charge, momentum, impulse 14. An object has a weight of 50 N on the Earth and a second object has a weight of 50 N on the moon. Which has the greater mass? 15. A car is being pulled by a force, suddenly the mass of the car doubles, what will happen to the cars acceleration? 16. A table cloth can be pulled from under a glass without it moving. This happens because of?

4 Mathematics Questions: Motion: 1. A car is traveling at 12.0 m/s. It skids to a stop in 4.50 m. What is the car s acceleration? [-16 m/s2 ] 2. How much time is needed for a car to accelerate to 25 m/s if it starts from rest and accelerates at 3.5 m/s2? [7.1 s] 3. An arrow is shot upward at a speed of 6.50 m/s. A. How high will the arrow go? [2.15 m] B. How long will it be in the air? [1.33 s] C. What will be its speed when it returns to the same height? [-6.50 m/s] D. What is the acceleration of the arrow when it is at its highest? [-9.8 m/s2 ] 5. A ball is thrown horizontally from atop a roof that is 6.00 m high at a speed of 2.25 m/s. A. How long will it take to hit the ground? [1.11 s] B. How far from the base of the building will it land? [2.50 m] C. What will be its velocity when it hits the ground? [11.1 m/s] 6. A cannonball is launched horizontally from a tower with a speed of 100 m/s. A. How far downrange will the cannon ball be after 2.0 seconds? [200 m] B. If it lands 350 m from the base of the tower, how tall is the tower? [60 m]

5 Forces: 7. A rope whose tension is 65.0 N is pulling a 35.0 kg wagon. A. What will be the acceleration of the wagon if the surface is frictionless? [1.85m/s2 ] 8. A force of 20 N is needed to pull a 8.0 kg block at constant speed. A. What is the friction force on the object? [-20 N] 9. A helicopter is flying horizontally with a speed of 45.0 m/s at an altitude of 65.0 m. The pilot is trying to save a castaway on an island and drops a care package. How far from the island should the pilot drop in order for the package to land on the island? [164 m] 10. An 85.0 kg student is standing on a scale (Newton) in an elevator. What will the scale read if: A. The elevator is at rest? [833 N] B. The elevator accelerates upward at 3.0 m/s2? [1088 N] C. The elevator accelerates downward at 7.50 m/s2? [196 N] 11. A train starting from rest, accelerates at a rate of 1.5 m/s2 for 30 seconds. After this, the train continues at a constant velocity for 5 minutes more. The train then decelerates at a rate of 2.3 m/s2 until it is stopped. What distance did the train travel from start to stop?

6 Momentum: Key terms (know what they are and how they are determined): A. Impulse B. Momentum C. Change in momentum 1. Described what is conserved and what is not conserved in the following: A. Elastic collision. B. Inelastic collision. 2. A kg car is traveling at 15.0 m/s when it collides and sticks to 50.0 kg garbage can that is at rest. What is the velocity of the masses immediately after the collision? [14.6 m/s] 3. A force of 850. N is applied for 2.30 seconds to a mass of 105 kg initially traveling at 1.50 m/s. What is the new velocity of the object? [20.1 m/s]

7 4. A 9.45 kg rifle fires a kg bullet with a muzzle velocity of m/s. With what velocity will the rifle recoil? [-5.95 m/s] 5. Ignoring friction, a 3.40 kg ball is rolling to the right at 2.00 m/s. A second ball (m = 1.25 kg) is at rest and collides with the first ball. What will be the velocity of both after the collision?? [0.92 m/s and 2.9 m/s] 6. A kg baseball is traveling at 40.0 m/s towards a batter. He hits it and it returns at 75.0 m/s. A. What is the change in momentum of the ball? [86.3 kg m/s] B. If the bat is in contact with the ball for 5.50 ms, how much force does it deliver? [15,700 N]

8 7. An 8 kg ball is traveling to the right at 5 m/s. It then collides elastically with a 4 kg ball traveling to the right at 2 m/s. A. What is the total momentum before? [48 kg m/s] B. What is the velocity of the center of mass? [+ 4 m/s] C. What will be the velocity of both balls after the collision? [v8 = 3 m/s, v4 = 6 m/s] D. What is the total momentum after the collision? [48 kg m/s] 8. Determine the velocity of all vehicles after the following occurs 600 kg 750 kg 1500 kg 15 m/s Inelast 6 m/s Elastic 2 m/s ic [vcar = vsuv = 1.6 m/s, vtruck =9.6m/s]

9 Gravitation Key terms (know what they are and how they are determined): A. Gravitational force B. Acceleration due to gravity 9. What is the acceleration due to gravity (g) on the surface of Venus (mv = 4.87x10 24 kg, RV = 6.05x10 3 km)? [8.87 m/s 2 ] 10. The force of gravity between two bodies is 5 N. The mass of each body is 67,000 kg. How far apart are the two bodies? 11. The g on a planet is 14.5 m/s 2. The planet has the same mass as the Earth. What is its radius? [0.24 m] [5.25x10 6 m] 12. A satellite with a mass of 300. kg is in a circular orbit 5.64x10 6 m from the Earth s center. A. What is the gravitational force on the satellite? [3761 N]

10 Electrostatics: 13. Calculate the strength and direction of the electric field m to the right of a 1.00 C electric charge. 14. Calculate the distance from a 3.00 C electric charge where the electric field strength is 1.09 x 1011 N/C. 15. An object with a charge of 2.00 C is separated from a second object with the same charge by a distance of 1.50 m. What is the electric force acting between the charges? Is the force an attractive or repulsive force? 16. An object with a charge of 1.50 x 10-2 C is separated from a second object with a charge of x 10-2 C by a distance of m. Calculate the force acting between the charges. Is the force attractive or repulsive? 17. Two identical charges are separated by a distance of 1.00 m. A repulsive force of 3.60 N acts between the charges. What is the magnitude of each of the charges

11 Momentum Continued: 1. The condition necessary for the conservation of momentum in a given system is that A) energy is conserved. D) internal forces equal external forces. B) one body is at rest. E) None of these is correct. C) the net external force is zero. Answer: C 2. Momentum is conserved in which of the following? A) elastic collisions D) collisions between automobiles B) inelastic collisions E) All of these are correct. C) explosions 3. A boy and girl on ice skates face each other. The girl has a mass of 20 kg and the boy has a mass of 30 kg. The boy pushes the girl backward at a speed of 3.0 m/s. As a result of the push, the speed of the boy is A) zero B) 2.0 m/s C) 3.0 m/s D) 4.5 m/s E) 9.0 m/s Answer: B Answer: D 4. A golfball and a Ping-Pong ball are dropped in a vacuum chamber. When they have fallen halfway to the floor, they have the same A) speed. B) potential energy. C) kinetic energy. D) momentum. E) speed, potential energy, kinetic energy, and momentum. Answer: A 5. In any and all collisions of short duration and for which it is true that no external forces act on the collision participants, A) kinetic energy is conserved. B) both momentum and kinetic energy are conserved. C) neither momentum nor kinetic energy is conserved. D) the relative velocities before and after impact are equal and oppositely directed. E) momentum is conserved. 6. For a system consisting of two particles that undergo an elastic collision, A) momentum is conserved but the total energy is not conserved. B) neither the kinetic energy nor the momentum is conserved. C) neither the total energy nor the momentum is necessarily conserved. D) the mechanical energy is conserved but momentum is not conserved. E) both kinetic energy and momentum are conserved.

12 7. If a body moves in such a way that its linear momentum is constant, then A) its kinetic energy is zero. B) the sum of all the forces acting on it must be zero. C) its acceleration is greater than zero and is constant. D) its center of mass remains at rest. E) the sum of all the forces acting on the body is constant and nonzero. Answer: B 8. An object of mass M1 is moving with a speed v on a straight, level, frictionless track when it collides with another mass M2 that is at rest on the track. After the collision, M1 and M2 stick together and move with a speed of A) v B) M1v C) (M1 + M2)v/M1 D) M1v/(M1 + M2) E) M1v/M2 Answer: D 9. A 40-kg girl, standing at rest on the ice, gives a 60-kg boy, who is also standing at rest on the ice, a shove. After the shove, the boy is moving backward at 2.0 m/s. Ignore friction. The girl's speed is A) zero B) 1.3 m/s C) 2.0 m/s D) 3.0 m/s E) 6.0 m/s Answer: D 10. A moving particle is stopped by a single head-on collision with a second, stationary particle, if the moving particle undergoes A) an elastic collision with a second particle of much smaller mass. B) an elastic collision with a second particle of much greater mass. C) an elastic collision with a second particle of equal mass. D) an inelastic collision with a second particle of any mass. Answer: C 11. Two cars of equal mass travel in opposite directions at equal speeds. They collide in a perfectly inelastic collision. Just after the collision, their velocities are A) zero. B) equal to their original velocities. C) equal in magnitude but opposite in direction to their original velocities. D) less in magnitude and in the same direction as their original velocities. E) less in magnitude and opposite in direction to their original velocities. Answer: A 12. Two equal masses travel in opposite directions with equal speed. If they collide in a perfectly elastic collision, then, just after the collision, their velocities will be A) zero. B) equal to their original velocities. C) equal in magnitude but opposite in direction to their original velocities. D) less in magnitude and in the same direction as their original velocities. E) less in magnitude and opposite in direction to their original velocities. Answer: C

13 13. Two equal masses travel in opposite directions with equal speeds. They collide in a collision that is between elastic and inelastic. Just after the collision, their velocities are A) zero. B) equal to their original velocities. C) equal in magnitude but opposite in direction to their original velocities. D) less in magnitude and in the same direction as their original velocities. E) less in magnitude and opposite in direction to their original velocities. 14. In an elastic collision of two objects, A) momentum is not conserved. B) momentum is conserved, and the kinetic energy after the collision is less than its value before the collision. C) momentum is conserved, and the kinetic energy after the collision is the same as the kinetic energy before the collision. D) momentum is not conserved, and the kinetic energy of the system after the collision differs from the kinetic energy of the system before the collision. E) the kinetic energy of the system after the collision depends on the masses of the objects. Answer: C 15. Two balls of equal mass are thrown against a massive wall with equal velocities. The first rebounds with a speed equal to its striking speed, and the second sticks to the wall. The impulse that the first ball transmits to the wall, relative to the second, is A) twice as great. D) four times as great. B) half as great. E) one-fourth as great. C) the same. Answer: A 16. A ball of mass m strikes a wall that is perpendicular to its path at speed +v and rebounds in the opposite direction with a speed v. The impulse imparted to the ball by the wall is A) 2mv B) mv C) zero D) mv E) 2mv Gravity Continued: 17. A woman whose weight on earth is 500 N is lifted to a height of two earth radii above the surface of the earth. Her weight A) decreases to one-half of the original amount. B) decreases to one-quarter of the original amount. C) decreases to one-fifth of the original amount. D) decreases to one-third of the original amount. E) decreases to one-ninth of the original amount. 18. The acceleration due to gravity at the surface of the earth is g. The radius of the earth is RE. The distance from the center of the earth to a point where the acceleration due to gravity is g/9 is A) RE B) 9RE C) RE/3 D) 3RE E) None of these is correct. Answer: D

14 19. At the surface of the moon, the acceleration due to the gravity of the moon is a. At a distance from the center of the moon equal to three times the radius of the moon, the acceleration due to the gravity of the moon is A) 9 a B) a /3 C) a /4 D) a /9 E) 27 a Answer: D 20. Suppose a planet exists that has half the mass of earth and half its radius. On the surface of that planet, the acceleration due to gravity is A) twice that on earth. D) one-fourth that on earth. B) the same as that on earth. E) none of these. C) half that on earth. Answer: A 21. You need an expression for the acceleration of the moon toward the earth. If the mass of the earth is Me, the mass of the moon Mm, the separation of the earth and moon r, and the appropriate gravitational constant is G, the correct expression for the moon's acceleration is A) GMeMm/r2 B) GMeMm 2 /r2 C) GMm/r2 D) GMe/r2 E) GMe/r2Mm Answer: D 22. The acceleration due to gravity in the vicinity of the earth A) varies directly with the distance from the center of the earth. B) is a constant that is independent of altitude. C) varies inversely with the distance from the center of the earth. D) varies inversely with the square of the distance from the center of the earth. E) is described by none of these. Answer: D 23. If a planet has a mass twice that of the earth and a radius four times that of the earth, the ratio of the acceleration due to gravity on the planet to that on the earth is A) 1/8 B) 1/2 C) 1/16 D) 2/1 E) 12/1 Answer: A 24. When two masses are a distance R apart, each exerts a force of magnitude F on the other. When the distance between them is changed to 4R, the force is changed to A) 16F B) 4F C) F/2 D) F/4 E) F/ According to Newton's law of universal gravitation, if the distance between two bodies is tripled, the gravitational force between them is A) unchanged. D) reduced to 1/3 its previous value. B) halved. E) None of these is correct. C) doubled.