Phys4AS17 jsong

Lab 20 Purpose: Predict an expression for the period of various physical pendulums. Verify the predicted value with the value getting from experiment. Learn to find out a physical pendulum’s period by calculating and by Logger Pro and video camera. Theory: In the first part, we need to get the center of mass of different shapes so that we can determine the momentum of inertia of them at the center of mass. By parallel axis theorem, we can derive the momentum of inertia of them at required center. Use the T=I α where α=ω^2*Θ to get the ω . And 2 π / ω is the result we want. We assume the parameter B as the base and H as height for an isosceles-triangle. When it comes to the semicircle, we use R stands for the radius of the semicircle. The result of each physical pendulums is followed. We will use Logger Pro for the experiment part to determine the period in the videos.                               ...

Lab 17 Purpose: To determine the moment of inertia of a right triangular thin plate around its center of mass, for two perpendicular orientations of the triangle. Introduction: In this lab, we will examine the parallel axis theorem with a special case. We will determine the moment of inertia of a right triangular at its edge. Then we will use parallel axis theorem to determine the moment of inertia around its center of mass. Comparing the result with the result of calculating the triangular part by evaluating the whole system’s moment of inertia. By comparing these two results, we can derive the conclusion that these two concepts are equal to each other in this lab. Setup Set the equipment up like the figure below. Mount the triangle on a holder and disk. The upper disk floats on a cushion of air. Process: Using LoggerPro to collect data when the apparatus is in the angular acceleration. Use the equation from Lab 16 as told in the guidance to derive the mom...

Lab18 Purpose: Measure the total moment of inertia and the acceleration a cart, which is tied to a string connected to a disk, will experience. Derive the time of acceleration with the parameters above. Introduction: For a system, the total moment of inertia is the sum of every parts’ moment of inertia. So when we need to calculate the system moment of inertia, we just need to divide it into small parts. To get the acceleration of the cart, we can use the equation torque=I α to calculate torque, then finally get the acceleration of the cart. Setup: Set equipment up like the plot below. Procedure: Measure the radius and height of each cylinder, which are the components of the whole system. It is hard to get the weight of each cylinder because they are welded together. Use the volume to calculate the percent of each cylinder. With the total weight, we can derive the weight of each part finally. The measurement and calculation is followed below. r...

Purpose: Learn the angular acceleration. Find out how the changing of hanging mass, rotating mass and the torque radius will influence on the angular acceleration. Introduction: In the angular acceleration lab, we usually use a disk. The changing of hanging mass, rotating mass and the torque radius affect on the angular acceleration. By changing one of those parameters and remaining others, we can find out how the chosen parameter will change the angular acceleration. For example, we can derive the influence of radius change by change the pulley’s size, which is made of the same material. After determining every parameters, we can finally find out how the changing of hanging mass, rotating mass and the torque radius will influence on the angular acceleration and verify it by the equation I*α=Torque where α stands for the angular acceleration. Setup: Set experiment devices as the following photo. Procedure: Measure the required parameters. Here are these para...

Purpose: Determine the firing speed of a ball from a spring-loaded gun. Introduction: In this ballistic pendulum lab, a ball is fired into a nylon block, which is supported by four vertical strings. The ball is captured by the block and they rise together through some angle. Use the equipment find out the angle. The kinetic energy of the system including block and ball transfers into gravitational potential energy during this process. So by measuring the angle we can derive the initial kinetic energy and finally, the speed. Procedure: First measure and record the mass of the ball and the block. Then set the ballistic pendulum up as following. After setting up, level the apparatus and the block. After all preparation done, pull back and lock the spring into position. Zero the angle indicator. Then put the ball into position. Then fire the ball into the block and record the maximum angle. Repeat these steps by four to five times to get a reliable average value. Cal...

Purpose: Look at a two-dimensional collision between two steel balls or steel and glass ball and determine if momentum and energy are conserved. Theory: An elastic collision is an encounter between two bodies in which the total kinetic energy of the two bodies after the encounter is equal to their total kinetic energy before the encounter. In this lab we will determine if the momentum and energy are conserved after collision by checking the data collected by the video. The momentum conserve both on the x-axis and the y-axis. So we can determine the change of the momentum in a two-dimensional collision by checking the total momentum in each direction. Setup: Set the stationary ball on a leveled glass table. Aim the rolling ball so that it hits the side of stationary ball. Use the phone’s slow motion capture function to collect data as a camera. Steel ball and steel ball: We firstly use two steel balls. After getting data from the phone, we use LoggerPro to analyze...