SIMPLE MECHANISMS - PRELAB Name : …………………………………………………………………………………...... Registration No. : …….………………………………………………………………………………. Group No. : …….………………………………………………………………………………. Date : …….………………………………………………………………………………. Course Unit : Kinematics and Dynamics (MP3010) Please attempt these questions prior to the lab session. Submit the answers of these question with the submission link provided along with the lab report. PRELAB QUESTIONS: 1. A mechanism, in engineering, is a device that transforms input forces and movement into a desired set of output forces and movement. What do you understand by the term kinematic pair? Differentiate between lower and higher pairs and provide 2 examples for each. ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... .................................................................................................................................................................... ................................................................................................................................................................... .................................................................................................................................................................... ................................................................................................................................................................... 2. The Geneva Mechanism can be considered as one of the simple mechanisms widely used in machine elements. Provide a sketch of a Geneva Mechanism and describe its motion. Name 2 applications where this mechanism can be used. ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... 1 ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... .................................................................................................................................................................. 3. Reciprocating engines make use of the slider crank mechanism. Indicate the crank, the slider and the connecting rod on a sketch of a slider crank mechanism. What is the main function accomplished by this mechanism? Name 2 other applications where slider crank mechanisms are used. ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... 4. What do you understand by the terms stroke and time ratio in context of a slider crank mechanism? ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... 5. Name few other simple mechanisms in general use. ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... .................................................................................................................................................................. 2 INERTIA IN ROTATIONAL MOTION PRELAB Name : …………………………………………………………………………………...... Registration No. : …….………………………………………………………………………………. Group No. : …….………………………………………………………………………………. Date : …….………………………………………………………………………………. Course Unit : Kinematics and Dynamics (MP3010) Please attempt these questions prior to the lab session. Submit the answers of these question with the submission link provided. PRELAB QUESTIONS: 1. Define the term moment of inertia: ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... 2. For a point mass the moment of inertia is just the mass times the square of the distance to the rotation axis. The moment of inertia of a rigid composite system is the sum of the moments of inertia of its component subsystems. Using calculus derive the moment of inertia for a uniform hollow cylinder about the axis through its center with mass m, inner radius r1 and outer radius r2. ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... 3 3. Deduce the equation for the moment of inertia of a solid cylinder about the axis through its center with radius r2 from the equation obtained in 2. ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... 4. Explain the concept of radius of gyration of an object. ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... 5. A method of measuring the moment of inertia of complex objects is to use a trifilar or bifilar pendulum. Explain how this is achieved. ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ................................................................................................................................................................. 6. Torque is equal to the moment of inertia I times angular acceleration α, it can also be calculated as the rotational force F times distance from axis of rotation r. Using this relationship, propose a experimental setup where a known falling mass, a stopwatch and a measuring tape can be utilized to measure the moment of inertia of a given object. ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... 4
