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Q1) A scientific statement that can never be changed is a scientific 1) theory. 2) principle. 3) hypothesis. 4) law. 5) None of the above choices are correct. Q2) Which one of the following terms is used to indicate the natural tendency of an object to remain at rest or in motion at a constant speed along a straight line? 1) velocity 2) force 3) acceleration 4) inertia 5) equilibrium Q3) The inertia of a body tends to cause the body to: 1) speed up 2) slow down 3) resist any change in its motion 4) fall toward Earth 5) decelerate due to friction Q4) When the bullet fired into the spiral tubes emerges, which path will it follow? 1) path A 2) path B 3) path C Q5) If no external forces are acting on a moving object it will 1) continue moving at the same speed. 2) continue moving at the same velocity. 3) move slower and slower until it finally stops. 4) more information is needed Q6) The force required to maintain an object at a constant velocity in free space is equal to 1) zero. 2) the mass of the object. 3) the weight of the object. 4) the force required to stop it. 5) none of these Q7) Under what condition(s) will an object be in equilibrium? 1) If it is either at rest or moving with constant velocity. 2) If it is moving with constant velocity or with constant acceleration. 3) Only if it is at rest. 4) Only if it is moving with constant velocity. 5) Only if it is moving with constant acceleration. Q8) A 50 N force and a 100 N force both act on the same object. What is the net force (total force) of the object? 1) 50 N 2) 100 N 3) 150 N 4) not enough information Q9) Rank the following situations (A, B, and C) according to the net force, greatest first. 1) B, C, A 2) C, A, B 3) C, B, A 4) A, C, B 5N 10 N 10 N 10 N 10 N A B C 10 N 5N 20 N Q10) The sketch below shows a painting staging in mechanical equilibrium. The staging weighs 300 N and supports two painters, one 250 N and the other 300 N. The reading on the left scale is 400 N. What is the reading on the right scale? 1) 250 N 2) 300 N 3) 350 N 4) 400 N 5) 450 N Q11) The last instant before an airplane crashes a passenger jumps out the door and falls only two feet to the ground. The passenger is 1) probably hurt or killed 2) unharmed 3) intelligent to think so fast 4) lucky to have studied physics Q12) Complete the following statement: The term net force most accurately describes 1) the mass of an object 2) the inertia of an object. 3) the quantity that causes displacement. 4) the quantity that keeps an object moving. 5) the quantity that changes the velocity of an object. Q13) A car rounds a curve while maintaining a constant speed. Is there a net force on the car as it rounds the curve? 1) No - its speed is constant. 2) Yes. 3) It depends on the sharpness of the curve and the speed of the car. Q14) An object moves with unchanging velocity so its acceleration is zero. Does it then have no forces acting on it? 1) yes, definitely 2) no, not necessarily Q15) A car starts up from rest along a straight highway with an acceleration of 1 m/s2. A second car comes racing past at a steady 120 km/hr. Which car has the larger net force acting on it? 1) the first car 2) the second car 3) neither, they both have no net force on them Q16) Suppose a particle is being accelerated through space by a 10-N force. Suddenly the particle encounters a second force of 10 N in the opposite direction from the first force. The particle with both forces acting on it 1) is brought to a rapid halt. 2) decelerates gradually to a halt. 3) continues at the speed it had when it encountered the 2nd force. 4) theoretically tends to accelerate toward the speed of light. 5) none of these Q17) A rock is thrown vertically into the air. At the very top of its trajectory the net force on it is 1) less than its weight. 2) more than its weight. 3) almost equal to its weight. Q18) Can the normal force on an object ever be greater than the object’s weight? 1) yes 2) no Q19) A box sitting on a table experiences a normal force, N. If you push down on the box, the normal force 1) increases. 2) stays the same. 3) decreases. Q20) A book is accelerated downward while it is in the palm of your hand. Which is larger, the book’s weight or the upward force exerted by your hand? 1) the weight of the book 2) your upward force on the book 3) neither, they are equal Q21) A rock is suspended from a string and moves downward at constant speed. Which of the following statements is true? 1) The tension is 0 N. 2) The tension points downward. 3) The tension is equal to the weight of the rock. 4) The tension is less than the weight of the rock. 5) The tension is greater than the weight of the rock. Q22) A rock is suspended from a string and it accelerates downward. Which of the following statements is true? 1) The tension points downward. 2) The tension is independent of the rock’s acceleration. 3) The tension is equal to the weight of the rock. 4) The tension is less than the weight of the rock. 5) The tension is greater than the weight of the rock. Q23) An object is being lowered on a cord at a constant speed. How does the tension T in the cord compare to the weight mg of the object? 1) T = mg 2) T > mg 3) T < mg velocity = constant Q24) A net force F is required to give an object with mass m an acceleration a. If a net force 6 F is applied to an object with mass 2m, what is the acceleration on this object? 1) a 2) 2a 3) 3a 4) 4a 5) 6a Q25) A rock is thrown straight up from the earth's surface. Which one of the following statements concerning the net force acting on the rock at the top of its path is true? 1) It is equal to the weight of the rock. 2) It is instantaneously equal to zero newtons. 3) Its direction changes from up to down. 4) It is greater than the weight of the rock. 5) It is less than the weight of the rock, but greater than zero N. Q26) An apple at rest weighs 1 N. The net force on the apple when it is in free fall is 1) 0 N. 2) 0.1 N. 3) 1 N. 4) 9.8 N. 5) none of these Q27) A sailboat is being blown across the sea at a constant velocity. What is the direction of the net force on the boat? 1) Left 4) Down 2) Right 5) Up 3) Net force is zero Q28) A rock weighs 30 N on Earth. A second rock weighs 30 N on the moon. Which of the two rocks has the greater mass? 1) the one on Earth 2) the one on the moon 3) They have the same mass. 4) not enough information to say Q29) A 10-kg brick and a 1-kg brick are both dropped in a vacuum. The force of gravity on the 10-kg brick is 1) the same as the force on the 1-kg book 2) 10 times as much as the force on the 1-kg book 3) zero Q30) As an object freely falls downward, its 1) velocity increases. 2) acceleration increases. 3) both of these. 4) none of these. Q31) A skydiver steps from a helicopter and falls for 5 seconds before reaching her terminal velocity. During this 5 second interval, her acceleration 1) is zero 2) is constant 3) increases 4) decreases 5) none of these Q32) A skydiver jumps from a high-flying plane. As her velocity of fall increases, her acceleration 1) increases. 2) decreases. 3) remains unchanged regardless of air resistance. Q33) A raindrop, baseball, bowling ball, and small car are dropped out of a C– 5 cargo plane. Which has the largest acceleration after reaching terminal speed? 1) Their accelerations are all zero. 2) The raindrop. 3) The baseball. 4) The bowling ball. 5) The small car. Q34) A car traveling at 100 km/hr strikes an unfortunate bug and splatters it. The force of impact is 1) greater on the bug 2) greater on the car 3) the same for both Q35) A moving van collides with a sports car in a high-speed head-on collision. Crash! During the impact, the truck exerts a force Ftruck on the car and the car exerts a force Fcar on the truck. Which of the following statements about these forces is true) 1) Ftruck = Fcar 2) Ftruck > Fcar 3) Ftruck < Fcar Q36) A bowling ball rolls down an alley and hits a bowling pin. Which statement below is true about the forces exerted during the impact? 1) The bowling pin exerts a larger force on the ball. 2) The bowling ball exerts a larger force on the pin. 3) The force that they exert on each other is the same size. 4) None of the above. Q37) A Mack truck and a Volkswagen traveling at the same speed have a head-on collision. The vehicle that undergoes the greatest change in velocity will be the 1) Volkswagen. 2) Mack truck. 3) same for both. Q38) Your hands push on a heavy box to slide it across the floor. The other member of the action/reaction pair is 1) friction pushing backward on the floor 2) gravity pulling downward on the box 3) the box pushing downward against the floor 4) the box pushing backward against your hands Q39) The attraction of a person’s body towards the Earth is called weight. The reaction to this force is 1) the person’s body pushing against the Earth’s surface 2) the Earth’s surface pushing against the person’s body 3) the person’s body pulling on the Earth 4) none of these Q40) As a ball falls, the action force is the pull of the Earth's mass on the ball. The reaction force is the 1) air resistance acting against the ball. 2) acceleration of the ball. 3) pull of the ball's mass on the Earth. 4) none of these Q41) A book at rest on the table has two forces on it: gravity pulling it down and the support force pushing it up. Are these forces an action/reaction pair? 1) yes 2) no Q42) Consider a car at rest. We can conclude that the downward gravitational pull of Earth on the car and the upward contact force of Earth on it are equal and opposite because 1) the two forces form an interaction pair. 2) the net force on the car is zero. 3) both of the above 4) neither of the above Q43) "In outer space, an astronaut pushes on his spacecraft, but it does not move because it exerts an equal and opposite force on the astronaut." True or False? 1) True 2) False 3) I'm not sure Q44) A horse exerts 500 N of force on a heavy wagon. The wagon pulls back on the horse with an equal force. The wagon still accelerates because 1) these forces are not an action-reaction pair. 2) nevertheless there is still an unbalanced force on the wagon. 3) the horse pulls on the wagon a brief time before the wagon reacts. 4) the wagon does not accelerate because these forces are equal and opposite. 5) the wagon is not alive. Q45) The “reaction" force does not cancel the “action" force because: 1) the action force is greater than the reaction force 2) they are on different bodies 3) they are in the same direction 4) the reaction force exists only after the action force is removed 5) the reaction force is greater than the action force