Hello, dear friend, you can consult us at any time if you have any questions, add WeChat: daixieit

MEC370 Dynamics laboratory 2023 2024

QUESTIONS- EXPAND AREA UNDER QUESTIONS AS YOU SEE FIT

Question 1: Calculation of the moment of inertia of the system (100 word max., 10 marks)

Consider what the system is? The shape of the two discs.. and their imperfections/ deviation form ideal geometrical shapes.

Marking scheme: 7/10 for correct value, 8/10 if correct unit also given, 10/10 if student also discussed what the system is and the possible imperfections of the disc

Question 2: Calculation of free-wheeling angular deceleration (100 words max., 10 marks)

Graphical calculation of slope in w(t) curve, neglecting the first few data point where w is rising (ie when external torque is applied) and the last ones, after the wheel has stopped spinning. Include chart title, axis titles and axis units. Present the graphs for at least three data acquisitions and give mean and stdev values for the deceleration slope, discuss why the wheel decelerates and also reasons for stdev. For each acquisition, display the full graph and also the ‘restricted graph’ for the deceleration segment where you fitted the decelerating slope.

Marking scheme: Correct slope value from data presented 7/10, with error 8/10 with correct narrative for deceleration and stdev 10/10

Question 3: Calculation of the frictional moment (no falling mass connected to discs) (100 words max., 10 marks)

Marking scheme: 7/10 for correct value, 8/10 with correct unit, 10/10 if valid discussion of assumptions

Question 4: Calculation of the angular acceleration and maximum angular speed WHEN THE MASS IS ATTACHED AND FALLING (100 words max., 20 marks)

Make sure you always position the mass in the same position, preferably just below the bench so that the mass and tray do not ‘catch’ the bench on their descent. Calculate graphically the angular acceleration a and maximum angular speed w_max, for the first rising segment of the curve. Present the graphs for at least three data acquisitions and give mean and stdev values for these a and w_max values. For each acquisition, display the full graph and also the ‘restricted graph’ for the rising segment where you fitted the accelerating slope.

Marking scheme: correct values from data presented 7/10, with error 8/10 with correct narrative 10/10

Question 5: Calculation of the theoretical angular acceleration with falling mass, dynamics theory compared to experimental value. (100 words max., 25 marks)

Follow section 2/3 in the ‘need to know’ information to solve eq. 1 and 2, eliminate T and calculate the theoretical value of the angular acceleration. Compare the obtained value to the experimental value determined in question 4, discuss differences between experimental and theoretical values.

Marking scheme: correct equations 10/25, with correct value, 18/25 and correct unit, 20/25. If the difference between theory and experimental value are also discussed 25/25

Question 6: Calculation of the theoretical maximum angular speed with falling mass, dynamics theory compared to experimental value. (100 words max., 25 marks)

Follow section 2/4 in the ‘need to know’ information to calculate the maximum angular speed. Compare the obtained value to the experimental value determined in question 4, Compare the obtained value to the experimental value determined in question 4, discuss differences between experimental and theoretical values.

Marking scheme: correct equations 10/25, with correct value, 18/25 and correct unit, 20/25. If the difference between theory and experimental value are also discussed 25/25