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Rotational Kinematics Lab--ZiTong Cheng

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 1. Use the velocity components to determine the direction of the velocity vector. Is it in the expected direction? The linear velocity for points at different radii (3 cm, 8 cm, and 15 cm) is 0.13 m/s, 0.23 m/s, and 0.42 m/s respectively. The direction of the linear velocity is tangent to the circular path, which is the expected behavior in rotational motion. From these values, the corresponding angular velocities are approximately: 4.33 rad/s at 3 cm 2.88 rad/s at 8 cm 2.80 rad/s at 15 cm 2. Analyze enough different points in the same video to make a graph of the speed of a point as a function of distance from the axis of rotation. What quantity does the slope of this graph represent? We created a graph showing how the speed of a point changes with distance from the axis of rotation, using the data: 3 cm → 0.13 m/s, 8 cm → 0.23 m/s, 15 cm → 0.42 m/s. The slope of this graph represents the angular velocity. Based on these points, the angular velocity is relatively consistent acros...
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Practice Exam 2--ZiTong Cheng

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  Answer from me
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Personal Contributions---ZiTong Cheng

 Our group is Steven Lee, Zitong Cheng and Derek Chen. And for my contributions: 1. I write all the code. 2. I do part of the vedio analyze. 3. I do conclusions like the equation we need to use, and how to express the motion of cart by equations. 4. I do the analyze of the energy loss vedio analyze and get final quation of the energy loss. 5. Add coding part into the ppt, and the pictures of equations on the ppt is all from me. conclusion: I do coding part and providing equation and part of data.
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Inclined track experiment----ZiTong Cheng

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 Questions： Equipment  You will have a meter stick, a stopwatch, cart masses and wooden blocks to create the incline. You may also use the video analysis equipment to estimate the effect of friction for measuring the efficiency.    Predictions  Whiteboard Question (odd):  Calculate the energy efficiency of the bumper (with friction and without) in terms of the least number of quantities that you can easily measure in the situation of an inclined track. Make a drawing of the cart on the level track before and after the impact with the bumper.  Define your system. Label the velocity and kinetic energy of all objects in your system before and after the impact. Write an expression for the efficiency of the bumper in terms of the final and initial kinetic energy of the cart. Write an expression for the energy dissipated during the impact with the bumper in terms of the kinetic energy before the impact and the kinetic energy after the impact. Whiteboard Ques...
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Angular velocity ----Even Table--->Linear velocity-----ZiTong Cheng

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1.Determine the final angular velocity of the ring/disk/shaft/spool system for each case after the weight hits the ground. How is this angular velocity related to the final velocity of the hanging weight?  Be sure to use an analysis technique that makes the most efficient use of your data and your time.  If your calculation incorporates any assumptions, make sure you justify these assumptions based on data that you have analyzed. Conclusion 2.In each case, how do your measured and predicted values for the final angular velocity of the system compare? 3.Of the three places you attached the string, which produced the highest final angular velocity?  Did your measurements agree with your initial prediction?  Why or why not?  What are the limitations on the accuracy of your measurements? 4.Given your results, how much does it matter where the starter cord is attached?  Why do you think the manufacturer chose to wrap the cord around the ring?  Explain your ...
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Coefficient of kinetic friction for wood on aluminum---ZiTong Cheng

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Questions: 1.For each new block mass, calculate the magnitude of the kinetic frictional force from the measured t.  Also determine the normal force on the block. 2.Graph the magnitude of the kinetic frictional force against the magnitude of the normal force, for a constant angle of incline.   On the same graph, show your predicted relationship. 3.For each angle (h), calculate the magnitude of the kinetic frictional force from the measured t.  Also determine the normal force on the block. 4.Graph the magnitude of the kinetic frictional force against the magnitude of the normal force for a constant block mass.   On the same graph, show your predicted relationship. 5.Calculate the uncertainty in your experimental technique.    Do your two graphs agree? 6.Conclusion:What is the coefficient of kinetic friction for wood on aluminum?   How does this compare to your prediction  Answer: 1 and 3 2. 4. 5. two graph not compeletely agree, but f...
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Hanging mass and Car Lab

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 ZiTong Cheng For this experiment, we first shot the video of the car's movement, then obtained the speed of the car through the video analysis software, then established the motion model and calculated the equation through desmos to obtain our estimate, and then wrote all the data in the table for comparison. The data we get: and the distance the hanging mass moved before it hits the ground is d = 0.275 +/- 0.01 m. Questions： 1. Comparison Between Predicted and Measured Velocity: When the hanging mass varied, the measured velocity was relatively close to the predicted velocity, but there was a 6-10% difference in most cases. The discrepancy became more noticeable as the hanging mass increased. Similarly, when the mass of the car changed, the measured values deviated from the predictions by around 15% in some cases. While most of the measurements were reasonably close to the initial predictions, the differences could be attributed to factors such as friction, irregularities on the...
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