Q&A Hero

Q: The variable r that appears in the equation F = Gm1m2/r2 is A) the straight-line distance between the centers of the two masses. B) the rate at which both objects are moving. C) the radius of the first mass. D) the radius of the second mass.

Q: The constant G that appears in the equation F = Gm1m2/r2 is A) smaller on the Moon than on Earth. B) the force of gravity. C) equal to 9.8 m/s2. D) the acceleration due to gravity. E) equal to 6.67 x 10-11 Nm2/kg2.

Q: The constant G that appears in the equation F = Gm1m2/r2 is A) smaller on the Moon than on Earth. B) the force of gravity. C) equal to g. D) the acceleration due to gravity. E) a universal constant.

Q: Two of your classmates, each 82 kg, are separated by 2 meters. The gravitational force of attraction between them in nano-newtons is A) 2.7 nN B) 1.4 nN C) 0.0 nN D) 164.7 nN E) 112.1 nN

Q: The gravitational pull of Earth acting on an object is zero when the object A) has zero acceleration. B) is in free fall. C) is midway between Earth and the Moon. D) is in orbit around Earth. E) none of these

Q: "Weightlessness" occurs when an object A) has zero acceleration. B) is in free fall. C) is midway between Earth and the Moon. D) loses weight.

Q: Newton's law of universal gravitation is believed to be applicable A) to the Milky Way only. B) on Earth and the Moon only. C) throughout the universe. D) to the solar system only. E) on Earth only.

Q: In the equation A = B/C, the B and C are said to be _______________ proportional. A) directly B) inversely C) not D) exactly

Q: In the equation A = B/C, the A and B are said to be _______________ proportional. A) directly B) inversely C) not D) exactly

Q: In the equation A = B/C, the A and C are said to be _______________ proportional. A) directly B) inversely C) not D) exactly

Q: According to Newton's second law, the force required to accelerate an object is equal to A) its acceleration divided by its mass. B) its mass times the acceleration. C) its mass divided by the velocity. D) its weight times the velocity.

Q: Newton's third law of motion states that the force pair acting on different objects consists of two forces that A) are under the influence of gravity. B) are equal and in the same direction. C) always produce an acceleration. D) are equal and in opposite directions.

Q: "For every action there is an equal and opposite reaction" is a statement of Newton's A) law of universal gravitation. B) first law. C) second law. D) third law.

Q: The relationship between mass and weight is given by the equation A) m = wg. B) w = m/g. C) g = mw. D) w = mg.

Q: Which of the following would be the same for a person on the Moon rather than on Earth? A) Maximum jumping height B) Weight C) The amount of time for an object to fall 2 meters from rest D) Mass E) Gravitational acceleration

Q: Which of the following would be different for a person on the Moon rather than on Earth? A) Weight B) Height C) Volume D) Mass

Q: If an object on Earth weighs 300 N, what is its weight in pounds? A) 67 B) 300 C) 31 D) 660 E) 1300

Q: If an unbalanced force of 5 N force acts on a 8-kg object, what is its acceleration? A) 40 m/s2 B) 0.63 m/s2 C) 1.6 m/s2 D) 13 m/s2 E) cannot be determined

Q: If the lever arm of a 5-N force is 7 m, what is the torque acting on the object due to this force? A) 35 Nm B) 0.71 Nm C) 1.4 Nm D) 12 Nm E) cannot be determined

Q: If an object of mass 9 kg has a velocity of 7 m/s, what is its linear momentum? A) 63 kg-m/s B) 1.3 kg-m/s C) 0.78 kg-m/s D) 16 kg-m/s E) cannot be determined

Q: ______________ principle explains why objects float or sink in a fluid. A) Newton's B) Pascal's C) Bernoulli's D) Archimedes'

Q: The buoyant force of an object is equal to the ______________ of the ______________ it displaces. A) mass; fluid B) weight; fluid C) mass; solid D) weight; solid

Q: An object will ______________ in a fluid if its average density is ______________ the density of the fluid. A) sink; greater than B) float; equal to C) sink; less than D) float; twice

Q: An object will ______________ in a fluid if its average density is ______________ the density of the fluid. A) float; greater than B) float; less than C) sink; less than D) sink; equal to

Q: On which planet (other than Earth) have air bags been deployed? A) Venus B) Mars C) Mercury D) Saturn

Q: An automobile air bag A) increases the contact time in stopping a person. B) reduces the impact force in a collision. C) increases the surface area of the impact force. D) does all of the above.

Q: It is generally easier to push an object once it is moving than when you are getting it started. This is because A) sliding friction is zero. B) sliding friction is less than static friction. C) static friction is less than sliding friction. D) static friction is zero.

Q: When you push on a stationary object on a horizontal surface and it doesn't move, what kind of force is most likely opposing your efforts? A) Static friction force B) Sliding friction force C) Lubricant friction force D) Gravitational force E) Normal Force

Q: If an object of mass 8 kg has an acceleration of 5 m/s2, what is the unbalanced force acting on it? A) 40 N B) 1.6 N C) 0.63 N D) 13 N E) cannot be determined

Q: If a person weighs 186 lb on Earth, that person's weight on the Moon would be A) 1116 lb. B) 93 lb. C) 31 lb. D) 186 lb. E) 93 lb.

Q: A spacecraft in space keeps going at the same velocity, even without firing its rockets, in accordance with the _______________ law of motion. A) fourth B) first C) second D) third

Q: Mass and weight on Earth's surface A) are the same thing. B) are defined solely by inertia. C) are explained by Newton's third law. D) differ in magnitude by a constant. E) are explained by Kepler's second law.

Q: When a net force on a moving object increases, the object will A) maintain the same velocity. B) always show an increase in speed. C) exhibit a change in speed and/or direction. D) maintain a constant acceleration.

Q: The SI base units making up the newton areA) kg m/s.B) g m/s2.C) kg m/s2.D) kg2/s.

Q: The acceleration produced by an unbalanced force acting on an object isA) inversely proportional to the mass of the object.B) directly proportional to the magnitude of the force.C) in the direction of the force.D) all of these.

Q: A constant net force acting on an object that is free to move will produce a constant A) speed. B) velocity. C) displacement. D) acceleration. E) distance.

Q: An automobile travels due north with a speed of 92 km/h that is decreasing. All forces considered, the unbalanced force acting on the auto is A) zero. B) southward. C) northward. D) downward. E) upward.

Q: An automobile travels due north with a speed of 93 km/h and an acceleration of 1.6 m/s2. All forces considered, the unbalanced force acting on the auto is A) zero. B) southward. C) northward. D) downward. E) upward.

Q: An automobile travels due north with a constant speed of 76 km/h. All forces considered, the unbalanced force acting on the auto is A) zero. B) southward. C) northward. D) downward. E) upward.

Q: Two equal and opposite forces of 3.0 N act on an object. The unbalanced force on the object A) is 3.0 N. B) is 0 N. C) is 5 N. D) is 6 N. E) cannot be determined from given information.

Q: Mass is a measure of A) inertia. B) force. C) grams. D) weight. E) kilograms.

Q: A mass is accelerated when ______________ acts upon the mass. A) a balanced force B) any force C) no force D) an unbalanced force E) none of these

Q: The natural tendency of an object to remain at rest or in motion with a constant velocity is called A) an external force. B) an unbalanced force. C) inertia. D) none of these.

Q: The essentials of the first law of motion were initially developed by A) Aristotle. B) Galileo. C) Newton. D) an unknown scientist.

Q: Dropped objects on the Moon fall at a slower rate than on Earth because of a smaller ______________.

Q: A rifle bullet shot horizontally has a vertical acceleration of ______________.

Q: Free-fall motion neglects ___________________.

Q: Physics deals with force, energy, motion, and ________________.

Q: Physics deals with matter, motion, force, and ________________.

Q: In free fall, the _______________ is constant.

Q: If an object has a constant velocity, then its acceleration is ______________.

Q: For there to be an acceleration, there must necessarily be a change in ______________.

Q: Speed is a(n) ______________ quantity.

Q: A compass registers ______________.

Q: A speedometer registers ______________.

Q: Distance is a(n) ______________ quantity.

Q: The straight-line distance and direction between two points are, together, called ______________.

Q: A continuous change in position is called ______________.

Q: When running and jumping to score, a basketball player seems to "hang" in the air because A) his or her acceleration is zero. B) his or her horizontal velocity is quite small. C) both components of motion are zero. D) his or her vertical velocity is quite small. E) levitation is possible with practice.

Q: A golfer hits a ball on a level fairway at an angle of 35 relative to the horizontal, and it lands on the green. Another golfer hits a ball with the same speed but at an angle of 55, and it lands on the green by the other ball. Which statement is accurate for this situation? A) One ball is in the air longer than the other. B) One ball experiences a greater acceleration while in free flight. C) One ball experiences a smaller acceleration while in free flight. D) Two balls hit at the same speed but different angles will always land in the same location. E) Two balls hit at the same speed but different angles can never land in the same location.

Q: A golfer hits a ball on a level fairway at an angle of 55 relative to the horizontal, and it lands on the green. Another golfer hits a ball with the same speed but at another angle, and it lands on the green by the other ball. What was the launch angle for the second golfer? A) 35 B) 25 C) 40 D) 45 E) 15

Q: In projectile motion, which of the following is notconstant? A) Vertical velocity B) Horizontal velocity C) Acceleration D) None of these

Q: Aprojectile's horizontal velocity component (ignoring air resistance) A) does not change. B) changes most rapidly near the bottom of its trajectory. C) changes at a variable rate. D) changes at a constant rate.

Q: A projectile's vertical velocity component A) changes most rapidly near the top of its trajectory. B) changes at a constant rate. C) changes most rapidly near the bottom of its trajectory. D) does not change.

Q: If the speed of an object in circular motion is increased by a factor of 5, its centripetal acceleration for the same radius will be multiplied by a factor of A) 0.04. B) 0.2. C) 2.24. D) 25. E) 5.

Q: The magnitude of the acceleration of an object moving in a circle at constant speed is A) inversely proportional to the speed squared. B) inversely proportional to the speed. C) inversely proportional to the radius of the circle squared. D) inversely proportional to the radius of the circle.

Q: The direction of the acceleration of an object moving in a circle at constant speed is A) changing, but pointing in a predictable direction. B) constant and pointing in only one direction. C) constant and pointing in two directions. D) none of these

Q: The magnitude of the acceleration of an object moving in a circle at constant speed is A) variable. B) directly proportional to the speed squared. C) directly proportional to the speed. D) directly proportional to the radius of the circle squared.

Q: Centripetal means A) center seeking B) pulls outward C) constant D) fast E) none of these

Q: An object travels in a circle of radius 10.0 m with a constant speed of 3.0 m/s. What is the direction of its acceleration? A) Toward the center of the circle B) Normal to the plane of the circle C) Insufficient data given for determination D) Tangential to the circle E) None of these

Q: In the equation ac= v2/rfor centripetal acceleration, the v stands for A) volume. B) very. C) speed. D) velociraptor.

Q: In the equation ac= v2/rfor centripetal acceleration, the rstands for A) diameter. B) distance. C) radius. D) rate.

Q: An object in uniform circular motion has A) constant acceleration. B) variable radial distances. C) constant velocity. D) constant speed.

Q: All the following may be represented by vectors except A) velocity. B) acceleration. C) speed. D) displacement.

Q: Which of the following statements is nottrue? A) Displacement has a direction and a magnitude. B) Acceleration has a magnitude only. C) Speed has a magnitude only. D) Velocity has a magnitude and a direction.

Q: The distance traveled by a dropped object in free fall is directly proportional to A) the time squared. B) its weight. C) its mass. D) none of these.

Q: An object that is moving with an acceleration different from zero will always have a(n) ______________ velocity. A) changing B) increasing C) constant D) decreasing

Q: A freely falling object has a constant acceleration of 9.8 m/s2. This means that A) the object's displacement changes by 9.8 m every second squared. B) the object's speed increases by 9.8 m/s each second. C) the object's acceleration increases by 9.8 m/s2each second. D) the object travels 9.8 m each second.

Q: An object is dropped from a vertical distance of 31.7 m above the ground, and it takes 2.54 sec to fall that distance. A second identical object to launched from the same height, with a horizontal velocity of 64.0 m/s. How long does the second object take to fall the 31.7 m? A) More than 2.54sec B) Almost 2.54 sec. C) Less than 2.54sec D) Exactly 2.54 sec E) Much less than 2.54sec

Q: A car is moving down a freeway in a straight line at a constant rate of 24.0 m/s for 4.0 s. Its acceleration is A) 9.8 m/s2. B) 9.8 m/s. C) zero. D) 24.0 m/s. E) 6.0 m/s2.