Lab 3- Practice Exam_ PHYS 1730 Lab Sections - Laboratory in Mechanics (Fall 2019 1)

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10/16/2019 Lab 3- Practice Exam: PHYS 1730 Lab Sections - Laboratory in Mechanics (Fall 2019 1) https://unt.instructure.com/courses/20982/quizzes/99127 1/14 Lab 3- Practice Exam Due No due date Points 30 Questions 30 Time Limit None Allowed Attempts 2 Attempt History Attempt Time Score LATEST Attempt 1 12 minutes 30 out of 30 Submitted Oct 16 at 11:56pm Take the Quiz Again 1 / 1 pts Question 1 Basic calculus is used to derive the equation vf^2 = vi^2 + 2ax where vf^2 means final speed vf squared; vi^2 means initial speed vi squared; x stands for distance traveled; and symbol a stands for the magnitude of constant acceleration. To begin the derivation of this equation one assumes which of the following definitions. a = dv/dt = constant v = dx/dt a = dv/dt = constant AND v = dx/dt Correct! Correct! a = (vf-vi)/t x = ((vf+vi)/2)*t 1 / 1 pts Question 2
10/16/2019 Lab 3- Practice Exam: PHYS 1730 Lab Sections - Laboratory in Mechanics (Fall 2019 1) https://unt.instructure.com/courses/20982/quizzes/99127 2/14 Can the magnitude of average velocity and average linear speed ever be equal? Yes Correct! Correct! No 1 / 1 pts Question 3 Is it possible to have a situation in which the velocity and acceleration have opposite signs? Yes Correct! Correct! No 1 / 1 pts Question 4 A ball is thrown vertically upward. What are its velocity and acceleration when it reaches maximum altitude? Acceleration is 9.8 m/s^2 towards the ground. Velocity is zero. Correct! Correct! Acceleration is zero. Velocity is zero. Acceleration is zero. Velocity is at a maximum. Acceleration is 9.8 m/s^2 away from the ground. Velocity is zero. Acceleartion is 9.8 m/s^2 towards the ground. Velocity is 9.8 m/s.
10/16/2019 Lab 3- Practice Exam: PHYS 1730 Lab Sections - Laboratory in Mechanics (Fall 2019 1) https://unt.instructure.com/courses/20982/quizzes/99127 3/14 1 / 1 pts Question 5 Given v = dx/dt it follows that dt = dx/v. Now given that a = dv/dt it follows that a = dv/(dx/v). Which of the following is true? adx = vdv Correct! Correct! adx = dv/v adv = dx/v a = v x = a/v 1 / 1 pts Question 6 Assuming a = constant and adx = vdv and given initial conditions that at time t = 0 distance x = 0 and initial speed = vi. At some later time t the final speed is vf. If you integrate both sides of the equation adx = vdv then ax = (vf^2 - vi^2)/2 Correct! Correct! ax^2 = vf^2 -vi^2 ax^2 = (vf - vi)^2 ax = (vf^2)/2 ax = vi^2/2
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10/16/2019 Lab 3- Practice Exam: PHYS 1730 Lab Sections - Laboratory in Mechanics (Fall 2019 1) https://unt.instructure.com/courses/20982/quizzes/99127 4/14 1 / 1 pts Question 7 The limit of the time rate of change of velocity as the time interval approaches zero defines instantaneous displacement speed velocity acceleration Correct! Correct! force 1 / 1 pts Question 8 The magnitude of the average velocity is equal to the average linear speed. True False Correct! Correct! 1 / 1 pts Question 9 The magnitude of the instantaneous velocity is equal to the instantaneous speed. True Correct! Correct! False
10/16/2019 Lab 3- Practice Exam: PHYS 1730 Lab Sections - Laboratory in Mechanics (Fall 2019 1) https://unt.instructure.com/courses/20982/quizzes/99127 5/14 1 / 1 pts Question 10 If acceleration is constant, the graph of acceleration versus time is: straight line with a positive slope curved line straight line with slope equal to zero Correct! Correct! straight line with a decreasing slope parabola 1 / 1 pts Question 11 The area under a velocity versus time curve is equal to: Final velocity Magnitude of the displacement Correct! Correct! Acceleration Time of travel Speed 1 / 1 pts Question 12 In MKS units velocity has units of __________ while acceleration has units of ___________.
10/16/2019 Lab 3- Practice Exam: PHYS 1730 Lab Sections - Laboratory in Mechanics (Fall 2019 1) https://unt.instructure.com/courses/20982/quizzes/99127 6/14 m; m/s m/s; m/s^2 Correct! Correct! m/s^2; m m/s^2; m/s m; m*s 1 / 1 pts Question 13 Consider a circular track with a radius of 200. m. A runner starts on the East side and runs around the track to a point diametrically opposite her starting point. She has run __________ m but her displacement is __________ m. 1257 m; 800. m West 628 m; 400. m West Correct! Correct! 628 m; 400. m East 314. m; 200. m West 400. m; 628 m East 1 / 1 pts Question 14 Consider a circular track with a radius of 200. m. A runner starts on the East side and runs around the track to a point diametrically opposite her starting point. She then runs the rest of the way around the track to complete a full lap. She has run __________ m but the magnitude of her displacement is _________ m.
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10/16/2019 Lab 3- Practice Exam: PHYS 1730 Lab Sections - Laboratory in Mechanics (Fall 2019 1) https://unt.instructure.com/courses/20982/quizzes/99127 7/14 1260 m; zero meters Correct! Correct! 1257 m; 1257 m 314 m; 400 m zero meters; 1260 m 400 m; 628 m 1 / 1 pts Question 15 Consider a circular track with a radius of 200. m. A runner starts on the East side and runs around the track to a point diametrically opposite her starting point. This half-lap takes 120. s to run. What is her average speed in m/s? 5.24 Correct! Correct! 3.33 3.14 6.28 10.48 1 / 1 pts Question 16 Consider a circular track with a radius of 200. m. A runner starts on the East side and runs around the track to a point diametrically opposite her starting point. This half-lap takes 120.s to run. Over the displacement, what is the magnitude of her average velocity in m/s?
10/16/2019 Lab 3- Practice Exam: PHYS 1730 Lab Sections - Laboratory in Mechanics (Fall 2019 1) https://unt.instructure.com/courses/20982/quizzes/99127 8/14 5.24 3.33 Correct! Correct! 3 6.28 10.48 1 / 1 pts Question 17 A jet aircraft rolls onto the end of a runway before accelerating down the runway to takeoff. At the point where the aircraft leaves the ground it is traveling 100. m/s. If the initial speed as the aircraft rolled onto the runway was 10. m/s and it accelerates uniformly for 20. s before takeoff; what is the magnitude of the acceleration during the time it takes to takeoff? 9.5 m/s^2 4.5 m/s^2 Correct! Correct! 10 m/s^2 5.5 m/s^2 5 m/s^2 1 / 1 pts Question 18 A flat object starting from rest slides down a frictionless 10.-m long surface inclined at an angle of 30.0 degrees. Assume the acceleration due to gravity is 9.80 m/s^2. In m/s^2 what is the acceleration of the sliding object down the inclined surface?
10/16/2019 Lab 3- Practice Exam: PHYS 1730 Lab Sections - Laboratory in Mechanics (Fall 2019 1) https://unt.instructure.com/courses/20982/quizzes/99127 9/14 9.80 m/s^2 8.50 m/s^2 5.70 m/s^2 4.90 m/s^2 Correct! Correct! 10 m/s^2 1 / 1 pts Question 19 A flat object starting from rest slides down a frictionless 10.-m long surface inclined at an angle of 30.0 degrees. Assume the acceleration due to gravity is 9.80 m/s^2. In m/s what is the linear speed of the sliding object at the end of 3.0 s? 29.4 m/s 25.5 m/s 17.1 m/s 15 m/s Correct! Correct! 15 cm/s 1 / 1 pts Question 20 A flat object starting from rest slides down a frictionless 10.0-m long surface inclined at an angle of 30.0 degrees. Assume the acceleration due to gravity is 9.80m/s^2. How long in seconds does it take the object to slide to the end of the 10.0-m long inclined surface?
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10/16/2019 Lab 3- Practice Exam: PHYS 1730 Lab Sections - Laboratory in Mechanics (Fall 2019 1) https://unt.instructure.com/courses/20982/quizzes/99127 10/14 1.57 s 1.0 s 2.02 s Correct! Correct! 4.9 s 2 s 1 / 1 pts Question 21 A flat object starting from rest slides down a frictionless a 10.-m long surface inclined at an angle of 30. degrees. Assume the acceleration due to gravity is 9.80 m/s^2. In m/s how fast is the object sliding when it reaches the end of the 10.-m long inclined surface? 98 m/s 49 m/s 9.9 m/s Correct! Correct! 4.9 m/s 2.5 m/s 1 / 1 pts Question 22 It was stated early that velocity is a vector, yet only a magnitude was calculated in the experiment. What is the direction of the velocity vector (along the airtrack)?
10/16/2019 Lab 3- Practice Exam: PHYS 1730 Lab Sections - Laboratory in Mechanics (Fall 2019 1) https://unt.instructure.com/courses/20982/quizzes/99127 11/14 toward the low end Correct! Correct! toward the high end straight down straight up horizontal 1 / 1 pts Question 23 As you tilt the airtrack higher, the acceleration of the glider increases; thus, acceleration is dependent on the angle of incline. Should it depend on mass as well? Yes No Correct! Correct! 1 / 1 pts Question 24 Which of the following affects the accuracy of the results of the experiment: Glider starting position Mass of glider Measurement of distance between the photogates A and B A and C Correct! Correct!
10/16/2019 Lab 3- Practice Exam: PHYS 1730 Lab Sections - Laboratory in Mechanics (Fall 2019 1) https://unt.instructure.com/courses/20982/quizzes/99127 12/14 1 / 1 pts Question 25 In this experiment which of the following was measured? actual length of glider length of glider that photogate sees Correct! Correct! 1 / 1 pts Question 26 True or False. When calculating the slope of a graph it is satisfactory to use actual experimental data points rather than arbitrary points that the line passes through. True False Correct! Correct! 1 / 1 pts Question 27 When determining the theoretical acceleration it was necessary to measure the height of the airtrack at two separate positions and their distance of separation. Why couldn't you simply measure one height at the top of the airtrack and use the length of the track for your distance of separation? The air track is not sitting on the table; second height is not zero. Correct! Correct! Need to take an average to obtain better results
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10/16/2019 Lab 3- Practice Exam: PHYS 1730 Lab Sections - Laboratory in Mechanics (Fall 2019 1) https://unt.instructure.com/courses/20982/quizzes/99127 13/14 1 / 1 pts Question 28 Why weren't you asked to weigh the gliders? The gliders have a standard mass that cancels out of the equations Mass has no affect on the outcome of this experiment Correct! Correct! 1 / 1 pts Question 29 Which of the following does not affect the accuracy of the results of the experiment: Glider starting position Friction of the airtrack and the height the airtrack is raised Mass of Glider Measurement of distance between the photogates B and C Correct! Correct! 1 / 1 pts Question 30 In part A you calculated average velocity. Was it important to know the glider length that the photogate saw? Yes No Correct! Correct!
10/16/2019 Lab 3- Practice Exam: PHYS 1730 Lab Sections - Laboratory in Mechanics (Fall 2019 1) https://unt.instructure.com/courses/20982/quizzes/99127 14/14