Speed and velocity Knowledge-Based Download PDF

Questions

1. 1.

   An object moving along a straight line smoothly changes its velocity from $-12\text{ m/s}$ to $+12\text{ m/s}$. Which statement correctly describes how the object's speed changes during this process?

   • A) The speed remains constant at 12 m/s throughout the entire motion.
   • B) The speed increases continuously from -12 m/s to +12 m/s.
   • C) The speed decreases to zero and then increases back to 12 m/s.
   • D) The speed remains zero until the velocity becomes positive.
2. 2.

   If an object's instantaneous velocity is equal to its average velocity at every point in time throughout a given interval, which statement must be true about its motion during that interval?

   • A) The object moves along a curved path at a constant speed.
   • B) The object moves along a straight line with a constantly increasing speed.
   • C) The object completes a closed circular loop at a constant speed.
   • D) The object moves along a straight line with a constant speed and an unchanging direction.
3. 3.

   A driver notes that the vehicle's odometer reading increases by 120 km during a 2.0-hour trip along winding roads. Which physical quantity can be determined directly from this information alone?

   • A) The magnitude of the vehicle's average velocity
   • B) The vehicle's average speed
   • C) The vehicle's instantaneous velocity at any point
   • D) The vehicle's instantaneous speed at the midpoint of the trip
4. 4.

   A truck travels along a straight road at a constant speed of 60 km/h for 2.0 hours, and then continues in the same direction at a constant speed of 90 km/h for 1.0 hour. What is the truck's average speed for the entire 3.0-hour trip?

   • A) 75 km/h
   • B) 72 km/h
   • C) 80 km/h
   • D) 70 km/h
5. 5.

   Which statement correctly defines an object's instantaneous velocity in relation to its average velocity?

   • A) It is the average velocity evaluated over the entire duration of the motion.
   • B) It is the arithmetic mean of the initial and final velocities over a finite time interval.
   • C) It is the limiting value of the average velocity as the elapsed time interval approaches zero.
   • D) It is the ratio of the total distance traveled to an infinitesimally small time interval.
6. 6.

   A cyclist rides along a path at a constant speed of 12 m/s for 30 s and then stops to rest for 10 s. What is the cyclist's average speed for the entire 40 s time interval?

   • A) 9.0 m/s
   • B) 12 m/s
   • C) 6.0 m/s
   • D) 8.0 m/s
7. 7.

   A cart moves along a straight track aligned with an x-axis. If the cart travels from an initial position of x = -20 m to a final position of x = 40 m in a time interval of 12 s, what is its average velocity?

   • A) +1.7 m/s
   • B) +3.3 m/s
   • C) +5.0 m/s
   • D) +60 m/s
8. 8.

   A drone flies 300 m due north and then 400 m due east in a total time of 50 s. What is the magnitude of the drone's average velocity for the entire flight?

   • A) 2 m/s
   • B) 6 m/s
   • C) 10 m/s
   • D) 14 m/s
9. 9.

   An object moves along a straight coordinate axis. If its average velocity over a time interval is positive, which of the following statements must be true?

   • A) The object moved in the positive direction at every instant during the interval.
   • B) The object's final position coordinate is greater than its initial position coordinate.
   • C) The object's instantaneous speed remained constant throughout the interval.
   • D) The object's total distance traveled is less than the magnitude of its displacement.
10. 10.

    For an object moving along a one-dimensional coordinate axis, which of the following quantities can take a negative value to indicate the direction of motion?

    • A) Total distance traveled
    • B) Average velocity
    • C) Instantaneous speed
    • D) Average speed
11. 11.

    An object moves from point A to point B along three different paths of unequal length, taking the exact same time interval for each journey. Which statement correctly compares the average velocity and average speed of the object for these three paths?

    • A) Both the average velocity and the average speed are the same for all three paths.
    • B) The average velocity is the same for all three paths, but the average speed is different for each path.
    • C) The average speed is the same for all three paths, but the average velocity is different for each path.
    • D) Both the average velocity and the average speed are different for each path.
12. 12.

    A car travels the first 60 km of a straight route at a constant speed of 30 km/h and the remaining 60 km at a constant speed of 60 km/h. What is the car's average speed for the entire 120 km journey?

    • A) 40 km/h
    • B) 45 km/h
    • C) 48 km/h
    • D) 50 km/h
13. 13.

    Which of the following statements describes a physically possible state of motion for an object moving along a straight line?

    • A) The object has a negative velocity and a positive speed.
    • B) The object has a positive velocity and a negative speed.
    • C) The object has a non-zero velocity and a speed of zero.
    • D) The object has an average speed that is strictly less than the magnitude of its average velocity over a time interval.
14. 14.

    Which statement correctly describes the relationship between an object's instantaneous speed and the magnitude of its instantaneous velocity at any given moment?

    • A) The instantaneous speed is always equal to the magnitude of the instantaneous velocity.
    • B) The instantaneous speed is greater than the magnitude of the instantaneous velocity whenever the object travels along a curved path.
    • C) The instantaneous speed is equal to the magnitude of the instantaneous velocity only when the object travels at a constant velocity.
    • D) The instantaneous speed is less than the magnitude of the instantaneous velocity whenever the object is decelerating.
15. 15.

    Which statement best explains why a vehicle's standard speedometer measures instantaneous speed rather than instantaneous velocity?

    • A) It measures the total distance traveled over a trip rather than the rate of motion at a specific instant.
    • B) It indicates how fast the vehicle is moving but does not provide its direction of travel.
    • C) It calculates the net displacement divided by the total time taken for the journey.
    • D) It yields accurate measurements only when the vehicle travels along a perfectly straight path.
16. 16.

    Under which of the following conditions is the average speed of an object equal to the magnitude of its average velocity over a given time interval?

    • A) When the object moves in a straight line without reversing its direction of motion.
    • B) When the object moves at a constant speed along any closed path.
    • C) When the object moves back and forth along a straight line and returns to its starting point.
    • D) When the object moves along a curved path with a constant rate of acceleration.
17. 17.

    Two trains travel along parallel straight tracks at a constant rate of 15 m/s, with one moving north and the other moving south. Which statement accurately compares their speeds and velocities?

    • A) Both trains have the same velocity because their rates of motion are identical.
    • B) The trains have different speeds because they are traveling in opposite directions.
    • C) The trains have the same speed because their magnitudes of motion are equal, but different velocities because their directions differ.
    • D) Both trains have the same velocity and the same speed because direction does not affect velocity along straight lines.
18. 18.

    A car moves along a curved racetrack at a constant speed of 25 m/s. Which statement correctly describes the car's speed and velocity during this turn?

    • A) Both its speed and its velocity are constant because it covers equal distances in equal time intervals.
    • B) Its velocity is constant, but its speed changes because distance along a curve exceeds displacement.
    • C) Neither its speed nor its velocity is constant because travel along a curve alters both quantities.
    • D) Its speed is constant, but its velocity is changing because the direction of motion alters continuously.
19. 19.

    A remote-controlled car travels 180 m due east in 30 s and then immediately turns around, traveling 60 m due west in 10 s. What are the average speed and the magnitude of the average velocity of the car for the entire 40 s journey?

    • A) Average speed is 3 m/s, and average velocity magnitude is 6 m/s.
    • B) Average speed is 6 m/s, and average velocity magnitude is 6 m/s.
    • C) Average speed is 4 m/s, and average velocity magnitude is 2 m/s.
    • D) Average speed is 6 m/s, and average velocity magnitude is 3 m/s.
20. 20.

    An athlete runs one complete lap around a 400 m circular track in a time of 50 s. What are the athlete's average speed and the magnitude of their average velocity during this run?

    • A) Average speed is 0 m/s, and average velocity magnitude is 8 m/s.
    • B) Average speed is 8 m/s, and average velocity magnitude is 8 m/s.
    • C) Average speed is 8 m/s, and average velocity magnitude is 0 m/s.
    • D) Average speed is 0 m/s, and average velocity magnitude is 0 m/s.