Ex 2D: Open this graph match on Logger Pro and have a classmate try to match it. The spring constant can be determined experimentally by allowing the mass to hang motionless on the spring and then adding additional mass and recording the additional spring stretch as shown below. Trial V: Graph Matching Take turns trying to match the graphs until the match is as close as possible. On the other side of the card, students record a negative change in their learning, such as a concept that needs more clarification or a part of the activity that was particularly difficult. What was Harry's distance for the trip? The assignment is meant to act as a formal assessment for mastery of kinematics curves, so it will be collected and graded for accuracy during the next class period. Predict how person A's velocity graph will change and check your prediction. Mass and Spring A mass suspended at the end of a spring will stretch the spring by some distance y.
Therefore, the positive direction in this case is down and the initial position A in Fig. Whiteboards of Motion Lab Results Sit with your lab group and prepare a whiteboard of the following: Sketch the original position vs. Since the velocity vector is changing in time, the object in uniform circular motion is accelerating. Once you've talked it over, go ahead and write down the letter of the graph that you think is the best representation of the man's change in position over time. Add one-third this mass to the oscillating mass before calculating the period of oscillation. What would the position vs.
Notice that in the relationship between T and m is not linear. Figure 1 compares the motion in the presence of a centripetal force to the resulting motion of a body if the centripetal force were to cease suddenly. After looking around the room and informally assessing that everyone has written down what our moving man is doing, I move on to show them. The position of the oscillating object varies sinusoidally with time. Theory predicts and experience verifies that if one-third the mass of the spring were added to the mass m in , the period will be the same as that of a mass of this total magnitude, oscillating on a.
I have the already loaded and displayed on a screen at the front of the room when the students walk in. The bottom of the base is provided with adjustable screws that can be used to level the entire apparatus. The activity is done in silence so that students can really personalize and consider their responses without inside influences. When students bring the cards forward they grab a copy of. Partners work best for this activity so that each student can be actively engaged throughout the work time. The pointer can be moved along the slot and positioned just under the tip of the rotating mass. Finishing this and discuss the implications.
Many objects oscillate back and forth. Doing this quick assessment gives me an idea of my students' comfort levels with motion graphs. This is shown graphically in the position-versus-time plot in Fig. In this experiment you will determine what variables must be known to determine the centripetal force required to keep a mass moving in a circular path with a constant speed. Today's activity allows students to visualize motion and its correspondence to kinematics graphs while working with someone new.
In this lab, you will analyze a simple pendulum and a spring-mass system, both of which exhibit simple harmonic motion. Notice that the magnitude of the velocity vector is not changing. Before we start the activity, I assign partners using the that already has my students' names loaded. The length L of the simple pendulum is measured from the point of suspension of the string to the center of the bob as shown in Fig. As the computers are booting I pass out the so that each student receives a copy.
How do the slopes compare for the different angle of ramp? By using the centripetal force apparatus you can measure the frequency of rotation of an object moving in a circular path of a known radius. I save these cards and read them during my next free time so that I can adjust my teaching and the assignment if needed. Can you create a velocity vs. Figure 7 : Experimental set-up for a simple pendulum If the bob is moved away from the rest position through some angle of displacement θ as in Fig. Lab 7 - Simple Harmonic Motion Introduction Have you ever wondered why a grandfather clock keeps accurate time? I present this information and the students are passive at this point, so that the entire class has a clear understanding of what the moving man in our example is doing.
What would the position vs. I do, however, ask students to raise their hand if they got at least one of the graphs correct. We use MacBook Pro's in my district, so my students are familiar with how the computer and cart organization works. On the right side of the card students put a minus sign followed by a delta sign. According to Newton's second law the net force must therefore be zero. Figure 2 shows five critical points as the mass on a spring goes through a complete cycle.
The motion of the pendulum is a particular kind of repetitive or periodic motion called simple harmonic motion, or. For example, if I ask students to draw the position v. And, if I display the random generator on the front board, there is an element of suspense as the partners are being assigned. My students don't need much guidance with this since they are familiar with the process, so it only takes a minute or two for everyone to clean up. For example, if a student claims in the conclusion that a constant velocity results in a linear position vs.
If the mass of the spring is much smaller than the oscillating mass, you do not have to add one-third the mass of the spring. The forces acting on the bob are the force of gravity and the tension force of the string. See the free-body diagram in Fig. The maximum displacement A is called the amplitude. Conceptually, using parallel and perpendicular coordinates is convenient because the parallel force is responsible for changes in speed and the perpendicular force or centripetal force is responsible for changes in direction. Some complicated motions like turbulent water waves are not considered simple harmonic motion.