Biology Forums - Study Force

A 50.0-g ball traveling at 22.0 m/s is bounced off a brick wall and rebounds at 21.0 m/s. A high-speed camera records this event. If the ball is in contact with the wall for 2.50 ms, what is the average acceleration of the ball during this time interval?
 a. 1.72E+4 m/s2
  b. 3.44E+4 m/s2
  c. 8.60E+3 m/s2
  d. 1.72E+1 m/s2
  e. 4.30E+1 m/s2

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[Ques. 2] The value of an object's acceleration may be characterized in equivalent words by which of the following?
 a. displacement
  b. rate of change of displacement
  c. velocity
  d. rate of change of velocity

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[Ques. 3] A v vs. t graph is drawn for a ball moving in one direction. The graph starts at the origin and at t = 5 s the acceleration of the ball is zero. We know that at t = 5 s,
 a. the slope of the curve is non-zero.
  b. the velocity of the ball is not changing.
  c. the curve is not crossing the time axis.
  d. the curve is at v = 0, t = 0.

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[Ques. 4] An x vs. t graph is drawn for a ball moving in one direction. The graph starts at the origin and at t = 5 s the velocity of the ball is zero. We can be positive that at t = 5 s,
 a. the slope of the curve is non-zero.
  b. the ball has stopped.
  c. the acceleration is constant.
  d. the curve is at x = 0, t = 0.

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[Ques. 5] A European sports car dealer claims that his product will accelerate at a constant rate from rest to a speed of 100 km/hr in 8.00 s. What is the speed after the first 4.00 s of acceleration? (Hint: First convert the speed to m/s.)
 a. 27.8 m/s
  b. 41.7 m/s
  c. 20.9 m/s
  d. 13.9 m/s
  e. 6.95 m/s

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[Ques. 6] A European sports car dealer claims that his car will accelerate at a constant rate from rest to 100 km/h in 8.00 s. If so, what is the acceleration? (Hint: First convert speed to m/s.)
 a. 3.47 m/s2
  b. 6.94 m/s2
  c. 5.21 m/s2
  d. 10.4 m/s2
  e. 8.68 m/s2

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[Ques. 7] Consider the magnitude of the average speed, vavg, speed, mag, and the magnitude of the average velocity, vavg, velocity, mag, for the same trip. Which of the following is always true?
 a. vavg, speed, mag = vavg, velocity, mag
 b. vavg, speed, mag  vavg, velocity, mag
 c. vavg, speed, mag  vavg, velocity, mag
 d. none of the above

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[Ques. 8] On a position-versus-time graph, the slope of the straight line joining two points on the plotted curve that are separated in time by the interval t, is which of the following quantities?
 a. average steepness
  b. average velocity
  c. instantaneous velocity
  d. average acceleration

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[Ques. 9] Changing the positive direction in a reference frame to the opposite direction does not change the sign of which of the following quantities?
 a. velocity
  b. average velocity
  c. speed
  d. displacement

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[Ques. 10] A ball is thrown vertically upwards at 19.0 m/s. For its complete trip (up and back down to the starting position), its average velocity is:
 a. 19.0 m/s.
  b. 9.5 m/s.
  c. 4.8 m/s.
  d. 14.3 m/s
 e. not given.

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Excellent response

Thank you