Q&A Hero

Q: An object with a mass of 8 kg is dropped and takes 5 s to hit the ground. Then another object with a mass of 16 kg is dropped from the same point. How long does it take to hit the ground?A) 5 sB) 10 sC) 3 sD) 25 sE) 125 s

Q: An object in free fall has A) a constant speed. B) a constant velocity. C) a velocity that changes 9.8 m/s each second. D) an acceleration that depends on its mass.

Q: A freely falling object A) has a uniformly increasing velocity. B) is unaffected by gravity. C) has a uniformly increasing acceleration. D) has a uniformly increasing displacement.

Q: If the magnitude of the velocity of an object increases, we may be sure that during the time of this increase, A) the object is accelerated. B) the acceleration of the object increases. C) the object is moving in a straight path. D) the object is changing direction. E) none of these

Q: Which of the following is a possible unit of acceleration? A) m/s2 B) m s C) m2/s D) m/s

Q: As a block slides down a 40 frictionless incline, its acceleration A) decreases with distance. B) remains constant. C) is greatest at the bottom of the incline. D) is greatest at the top of the incline.

Q: An object that is moving in a linear path with an acceleration in the direction of motion has a(n) ______________ velocity. A) constant B) increasing C) decreasing D) none of these

Q: An object that is moving in a linear path with an acceleration at a right angle to the motion has a(n) ______________ velocity. A) changing B) increasing C) decreasing D) constant

Q: An object that is moving in a linear path with an acceleration in the direction opposite to the motion has a(n) ______________ velocity. A) constant B) increasing C) decreasing D) none of these

Q: The distance traveled by an automobile moving at a constant velocity is A) directly proportional to the time. B) directly proportional to the time squared. C) inversely proportional to the time squared. D) inversely proportional to the time. E) none of these

Q: Which one of the following is true for deceleration? A) The acceleration is in the direction opposite the motion. B) The acceleration is zero. C) The acceleration is necessarily negative. D) The velocity remains constant.

Q: Velocity is similar to speed, but a ________ is also involved in velocity. A) acceleration B) direction C) position D) scalar

Q: For which of the following is the acceleration constant? A) Nonuniform speed B) Free fall C) Uniform circular motion D) None of these

Q: An acceleration may result from A) a change in speed. B) a change in direction. C) a change in both speed and direction. D) all of these

Q: An automobile's acceleration cannotbe changed by using the A) gas pedal. B) brake pedal. C) steering wheel. D) stick shift. E) turn signal.

Q: An automobile's acceleration may be changed by using the A) windshield wipers. B) steering wheel. C) radio. D) horn.

Q: The rate at which an object's velocity changes with time is called its A) instantaneous velocity. B) motion. C) speed. D) acceleration.

Q: If the instantaneous velocity of an object is constant, then so is its A) velocity. B) distance. C) acceleration. D) displacement.

Q: If an object moves with constant velocity, A) its speed is constant. B) its direction is constant. C) its average speed is constant. D) its distance traveled per unit time is constant. E) all of these

Q: A speedometer indicates ______________ if the automobile is traveling forward. A) instantaneous acceleration B) instantaneous speed C) instantaneous velocity D) average speed E) average acceleration

Q: The magnitudes of two horizontal displacements are 1 m and 9 m, respectively. Given that the vectors may be in either the plus or the minus direction, they cannotbe added together to give a total displacement of A) 10 m. B) "8 m. C) 8 m. D) 9 m. E) 7 m.

Q: The straight-line distance and direction between two points are, together, called A) velocity. B) displacement. C) distance. D) acceleration.

Q: Distance covered per unit of time is called A) speed. B) acceleration. C) velocity. D) displacement.

Q: Average speed multiplied bytime gives A) average acceleration. B) displacement. C) instantaneous speed. D) distance.

Q: Displacement divided by time gives A) average acceleration. B) average velocity. C) average speed. D) average distance.

Q: The magnitude of a displacement is ______________ the magnitude of the distance traveled. A) always unequal to B) less than or equal to C) always equal to D) greater than or equal to E) none of these; the two cannot be compared.

Q: Motion necessarily involves A) a change in velocity. B) a change in speed. C) a change in direction. D) a change in position. E) all of these

Q: Which one of the following is notan area of physics? A) Mechanics B) Optics C) Algebra D) Acoustics

Q: An ant on a picnic table travels 30 cm eastward, then 15 cm northward, then 20 cm westward, and finally 15 cm southward. What is the magnitude of its net displacement?

Q: What is the displacement of a hiker who travels 3.0 km east and then 4.0 km north?

Q: A rock dropped down a well takes 1.8 s to hit the water. How far below the top of the well is the surface of the water?

Q: A stone is dropped from the top of a well that has water in it at a depth of 65.0 m. How long does it take the stone to reach the water?

Q: On the Moon, what is the approximate value for the acceleration due to gravity?

Q: A ball dropped from the top of a building hits the ground 8.0 s later. How high is the building (in meters)?

Q: The following are data for an accelerating car:t (s) 0 5 10 15 20------------------------v (m/s) 0 3 6 9 12a. Is this car undergoing uniform acceleration?b. If so, what is the acceleration?

Q: A car travels at a constant speed of 100.0 km/h around a circular track with a diameter of 1.00 km. What is the magnitude of the car's centripetal acceleration, and what supplies this?

Q: The following data refer to a car traveling west:t (s) 0 1 2 3 4--------------------------v (m/s) 30 25 20 15 10Find the magnitude and direction of the acceleration.

Q: A ball is thrown up in the air with an initial velocity of 78.4 m/s upward. How long does it take the ball a. to go up? b. to come down after reaching maximum height?

Q: An object is dropped (g= 9.80 m/s2) and falls for 5.00 s before hitting the ground. a. How far has the object fallen? b. What is the final velocity? c. What is the final acceleration?

Q: An automobile traveling on a straight, level road at 15 km/h speeds up to 90 km/h in 30 s. What was the magnitude of the auto's acceleration, in meters per second squared?

Q: On a trip, a family travels 200 km in 2.5 h on the first day, 300 km in 4.0 h on the second day, and 250 km in 3.5 h on the third day. What was the average speed, in kilometers per hour, for the total trip?

Q: A student travels from St. Louis to Indianapolis, a distance of 210 mi, in 6.0 h. The return trip over the same route takes 7.0 h. What is the average speed for a. the first half of the trip? b. the second half of the trip? c. the total trip?

Q: Because of air resistance, an object falling a great distance may reach a ______________ velocity.

Q: Under ideal conditions, a projectile with a given initial speed at an angle of 85 has the same range as a projectile at an angle of ______________ with the same initial speed.

Q: At the maximum height of a projectile launched at an angle to the horizontal, the projectile's velocity is in a ______________ direction.

Q: Two objects are in uniform circular motion at the same speed but at different radii. The one with the ______________ radius has the largest centripetal acceleration.

Q: A rifle bullet shot horizontally at a velocity of 9.8 m/s has a horizontal acceleration of ______________.

Q: For an object in uniform circular motion, the acceleration points toward ______________.

Q: The centripetal acceleration of an automobile in uniform circular motion on a flat circular track is supplied by ______________.

Q: The SI unit of centripetal acceleration is ______________.

Q: What two quantities are constant in uniform circular motion? ______________ and ______________

Q: ______________ acceleration is necessary for uniform circular motion.

Q: An object moving in a circle with a constant speed has a(n) ______________ directed toward the center of the circle.

Q: Temperature is an example of a(n) ______________ quantity.

Q: A(n) ______________ quantity has only magnitude.

Q: A(n) ______________ quantity has both magnitude and direction.

Q: On Earth, the magnitude of the velocity of a vertical projectile at its maximum height is equal to ______________.

Q: On Earth, the magnitude of the acceleration of a vertical projectile at its maximum height is equal to ______________.

Q: In straight-line motion, if a moving object speeds up, the direction of the acceleration is ______________ the direction of the velocity.

Q: In straight-line motion, if a moving object slows down, the direction of the acceleration is ______________ the direction of the velocity.

Q: The distance a dropped object travels is proportional to the ______________ of the time.

Q: For the multiplication of 8.936 m divided by 1.90 m, the result should be reported with how many significant figures? A) Two B) One C) Three D) Four E) Seven

Q: For the multiplication of 8.1 m times 6.4 m, the result should be reported with how many significant figures? A) Two B) One C) Three D) Four E) Seven

Q: For the multiplication of 8.481 m times 7.7 m, the result should be reported with how many significant figures? A) Two B) One C) Three D) Four E) Seven

Q: For the multiplication of 7.443 m times 8.00 m, the result should be reported with how many significant figures? A) Two B) One C) Three D) Four E) Seven

Q: A measurement of 0.00254 g is the same as A) 0.254 mg. B) 25.4 mg. C) 254 mg. D) 2.54 mg. E) none of these.

Q: The speed of light in a vacuum is 300,000,000 m/s. Represented in powers-of-10 notation, this isA) 30 x 108m/s.B) 3 x 107m/s.C) 30 x 106m/s.D) 3 x 108m/s.

Q: One megawatt contains how many watts? A) 103 B) 10-6 C) 106 D) 10-3

Q: One microgram (μg) contains how many grams? A) 10-3 B) 10-6 C) 10-9 D) 103

Q: Expressed in standard powers-of-10 notation and rounded to four significant figures, the number 0.00023648 is A) 2.364 103. B) 2.365 104. C) 2.365 10-4. D) 236.4 10-6.

Q: Rounding the number 200.601 to three significant figures A) gives 199. B) gives 200. C) gives 200.601 D) gives 201. E) cannot be done.

Q: When multiplying and/or dividing quantities, you should report A) the result rounded to the same number of digits as there are in the quantity with the greatest number of significant figures. B) all the digits that show on your calculator. C) only whole numbers. D) the result rounded to the same number of digits as there are in the quantity with the least number of significant figures.

Q: A method of expressing the accuracy of measured quantities is A) metric prefixes. B) derived units. C) significant figures. D) conversion factors.

Q: A relationship such as 1 in. = 2.54 cm is a(n) A) equivalence statement. B) base unit. C) derived unit. D) fundamental quantity.

Q: Density describes A) mass per unit volume. B) length per unit time. C) volume per liter. D) weight per mass.

Q: Which of the following quantities expressed in derived units includes the unit of length? A) Area B) Volume C) Speed D) Density E) All of these

Q: A metric ton (or tonne) is A) the same as a British ton. B) not defined. C) a mass unit. D) a weight unit.

Q: A derived unit A) involves only length. B) is a combination of units. C) applies only to density. D) is not found in the metric system.

Q: What is the mass of 25 cm3of pure water?A) None of theseB) 25 kgC) 25 gD) 25 mL

Q: The International System of Units (SI) has ______________ base units. A) four B) six C) seven D) five