Exam Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Hang from a pair of gym rings and the upward support forces of the rings will always 1) A) each equal your weight. B) each be half your weight. C) add up to equal your weight. 2) The force of friction on a sliding object is 10 N. The applied force needed to maintain a constant velocity is A) 10 N. B) more than 10 N. C) less than 10 N. 2) 3) A package falls off a truck that is moving at 30 m/s. Neglecting air resistance, the horizontal speed of the package just before it hits the ground is A) zero. B) more than 30 m/s. C) less than 30 m/s but larger than zero. D) about 30 m/s. E) More information is needed for an estimate. 3) 4) If your automobile runs out of fuel while you are driving, the engine stops but you do not come to an abrupt stop. The concept that most explains why is A) resistance. B) inertia. C) acceleration. D) gravity. 4) 5) If no external forces are acting on a moving object, it will 5) A) continue moving at the same velocity. B) continue moving at the same speed. C) move slower and slower until it finally stops. 6) It takes 6 seconds for a stone to fall to the bottom of a mine shaft. How deep is the shaft? 6) A) about 180 m B) about 120 m C) more than 200 m D) about 60 m 7) A hockey puck is set in motion across a frozen pond. If ice friction and air resistance are neglected, the force required to keep the puck sliding at constant velocity is A) zero. B) equal to its weight divided by its mass. C) equal to its weight. D) equal to the product of its mass times its weight. 7) 8) Disregarding air drag, how fast must you toss a ball straight up in order for it to take 2 seconds to return to the level from which you tossed it? A) 7.5 m/s B) 15 m/s C) 10 m/s D) 5 m/s E) 20 m/s 8) 1
9) If a projectile is fired straight up at a speed of 10 m/s, the total time to return to its starting position is about A) 20 seconds. B) 2 seconds. C) 1 second. D) 10 seconds. E) not enough information to estimate 9) 10) The muzzle velocity of a bullet fired from a new rifle is 100 m/s. Neglecting air resistance, at the end of one second a bullet fired straight up into the air will have traveled a distance of A) 100 m. B) 4.9 m. C) (100 + 4.9) m. D) (100-4.9) m. 10) 11) One half second after starting from rest, a freely falling object will have a speed of about 11) A) 20 m/s. B) 5 m/s. C) 2.5 m/s. D) 10 m/s. 12) A ball tossed vertically upward rises, reaches its highest point, and then falls back to its starting point. During this time the acceleration of the ball is always A) in the direction of motion. B) directed downward. C) directed upward. D) opposite its velocity. 12) 13) A car accelerates at 2 meters/s/s. Assuming the car starts from rest, how far will it travel in 10 s? A) 40 m B) 2 m C) 200 m D) 100 m E) 10 m 13) 14) If an object moves with constant acceleration, its velocity must 14) A) be constant also. B) change by varying amounts depending on its speed. C) change by the same amount each second. D) always decrease. 15) A ball is thrown upwards. Neglecting air resistance, what initial upward speed does the ball need to remain in the air for a total time of 10 seconds? A) about 100 m/s B) about 50 m/s C) about 80 m/s D) about 110 m/s E) about 60 m/s 15) 2
16) Compared to a 1-kg block of solid iron, a 2-kg block of solid iron has twice as much 16) A) mass. B) volume. C) inertia. D) all of these 17) Compared to the mass of a certain object on Earth, the mass of the same object on the moon is 17) A) one sixth as much. B) six times as much. C) zero. D) the same. 18) A man leans over the edge of a cliff and throws a rock upward at 4.9 m/s. Neglecting air resistance, one second later the rock's speed is A) 14.7 m/s. B) 9.8 m/s. C) 4.9 m/s. D) zero. E) none of the above 18) 19) An object's weight may properly be expressed in units of 19) A) cubic centimeters. B) newtons. C) kilograms. D) meters. 20) An object is propelled along a straight-line path in space by a force. If the mass of the object somehow becomes twice as much, its acceleration A) doubles. B) halves. C) quadruples. D) stays the same. 20) 21) The force of friction on a sliding object is 10 newtons. The applied force needed to maintain a constant velocity is A) 10 N. B) more than 10 N. C) less than 10 N. 21) 22) An apple at rest weighs 1 N. The net force on the apple when it is in free fall is 22) A) 9.8 N. B) 0 N. C) 1 N. D) 0.1 N. 23) A 1-kg mass at the Earth's surface weighs 23) A) 10.8 N. B) 4.9 N. C) 1 N. D) 9.8 N. 3
24) A car has a mass of 1000 kg and accelerates at 2 meters per second per second. What is the magnitude of the net force exerted on the car? A) 1000 N B) 1500 N C) 2000 N D) 500 N 24) 25) The mass of a pet turtle that weighs 10 N is 25) A) about 10 kg. B) about 100 kg. C) about 1 kg. D) about 1000 kg. 26) If an object falling freely were somehow equipped with an odometer to measure the distance it travels, then the amount of distance it travels each succeeding second would be A) greater than the second before. B) less and less each second. C) constant. D) doubled. 26) 27) A rocket becomes progressively easier to accelerate as it travels upward from the ground mainly because A) the applied force on the rocket increases as burning of fuel progresses. B) the mass of the rocket decreases as fuel is burned. C) gravity becomes weaker with increased distance. 27) 28) Neglecting friction, a large block of ice and a small block of ice start sliding down an incline together. The heavier block will get to the bottom A) after the light block. B) before the light block. C) at the same time as the light block. 28) 29) 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 A) continues at the speed it had when it encountered the second force. B) theoretically tends to accelerate toward the speed of light. C) decelerates gradually to a halt. D) is brought to a rapid halt. 29) 30) A 1-kg rock that weighs 9.8 N is thrown straight upward at 20 m/s. Neglecting air resistance, the net force that acts on it when it is half way to the top of its path is A) more than 9.8 N. B) 9.8 N. C) less than 9.8 N. 30) 4
31) If an object of constant mass experiences a constant net force, it will have a constant 31) A) speed. B) velocity. C) acceleration. D) position. E) more than one of the above 32) If you are driving at 20 m/s and slam on your brakes and skid at 0.5 g to a full stop, the skidding time in seconds is A) more than 6. B) about 4. C) about 3. D) about 5. E) about 6. 32) 33) What horizontally-applied force will accelerate a 400-kg crate at 1 m/s2 across a factory floor against a friction force half its weight? A) 1600 N B) 600 N C) 2000 N D) 2400 N 33) 34) If less horizontal force is applied to a sliding object than is needed to maintain a constant velocity A) the object eventually slides to a stop. B) the object accelerates in the direction of the applied force. C) the friction force increases. D) none of the above 34) 35) A baseball player bats a ball with a force of 1000 N. The reaction force that the ball exerts against the bat is A) less than 1000 N. B) 1000 N. C) more than 1000 N. D) impossible to determine. 35) 36) An object following a straight-line path at constant speed 36) A) has zero acceleration. B) has no forces acting on it. C) has a net force acting upon it in the direction of motion. D) none of these 37) The attraction of a person's body toward Earth is called weight. The reaction to this force is 37) A) the person's body pushing against Earth's surface. B) the person's body pulling on the Earth. C) the Earth's surface pushing against the person's body. D) none of these 5
Figure 5-A 38) Arnold Strongman and Suzie Small each pull very hard on opposite ends of a massless rope in a tug-of-war. The greater force on the rope is exerted by A) Arnold, of course. B) Suzie, surprisingly. C) both the same, interestingly enough. 38) 39) A car traveling at 100 km/hr strikes an unfortunate bug and splatters it. The force of impact is 39) A) greater on the bug. B) the same for both. C) greater on the car. 40) A vehicle that weighs 4000 N on the surface of the Earth is travelling in outer space at a speed of 200 m/s. The smallest constant force that must be applied to stop it in 20 seconds is A) 40 N. B) 400 N. C) more than 4000 N. D) 4000 N. E) 20 N. 40) 41) A player hits a ball with a bat. The action force is the impact of the bat against the ball. The reaction to this force is the A) force that the ball exerts on the bat. B) grip of the player's hand against the ball. C) weight of the ball. D) weight of the bat. E) air resistance on the ball. 41) 42) Which of the following has the largest momentum relative to the Earth's surface? 42) A) a dog running down the street B) a tightrope walker crossing Niagara Falls C) a Mack truck parked in a parking lot D) the Science building on campus E) a pickup truck speeding along a highway 43) Suppose that a tiny gun made of a strong but very light material fires a bullet that is more massive than the gun itself. For such a weapon A) both conservation of energy and momentum would not hold. B) conservation of energy would not hold. C) conservation of momentum would not hold. D) recoil problems would be lessened. E) the target would be safer than the shooter. 43) 6
44) A piece of rope is pulled by two people in a tug-of-war. Each pulls with 400 N of force. What is the tension in the rope? A) 600 N B) 800 N C) 400 N D) zero 44) 45) Compared to falling on a stone floor, a wine glass may not break when it falls on a carpeted floor because the A) carpet provides a smaller impulse and a longer time. B) stopping time is longer on the carpet. C) carpeted floor provides a smaller impulse. D) stopping time is shorter on the carpet. 45) 46) A large metal ball is shot from a cannon with a short barrel. If the same ball were to be shot from cannon with a longer barrel, its muzzle velocity would be A) the same. B) less. C) more. D) impossible to determine without additional information. 46) 47) A 1-kg chunk of putty moving at 1 m/s collides with and sticks to a 5-kg bowling ball initially at rest. The bowling ball and putty then move with a momentum of A) more than 5 kg m/s. B) 0 kg m/s. C) 2 kg m/s. D) 1 kg m/s. E) 5 kg m/s. 47) 48) A rifle of mass 2 kg is suspended by strings. The rifle fires a bullet of mass 0.01 kg at a speed of 200 m/s. The recoil velocity of the rifle is about A) 0.01 m/s. B) 1 m/s. C) 0.001 m/s. D) 0.1 m/s. 48) 49) A 5000-kg freight car runs into a 10,000-kg freight car at rest. They couple upon collision and move with a speed of 2 m/s. What was the initial speed of the 5000-kg car? A) 6 m/s B) 8 m/s C) 4 m/s D) 5 m/s 49) 7
50) A golf ball moving forward with 1 unit of momentum strikes and bounces backward off a heavy bowling ball that is initially at rest and free to move. The bowling ball is set in motion with a momentum of A) more than 1 unit. B) 1 unit. C) less than 1 unit. D) not enough information 50) 51) A 1000-kg car moving at 10 m/s brakes to a stop in 5 s. The average braking force is 51) A) 5000 N. B) 2000 N. C) 1000 N. D) 4000 N. 52) A car traveling along the highway needs a certain amount of force exerted on it to stop it in a certain distance. More stopping force is required when the car has A) more mass. B) less stopping distance. C) more momentum. D) all of these 52) 8