PocketLab in conjunction with a 33-45-78 RPM turntable is an ideal setup for studying centripetal acceleration. There are two videos that can be found in the Videos page of this web site. They show that (1) keeping radius constant implies that centripetal acceleration is proportional to the square of the velocity, (2) keeping velocity constant while varying the radius implies that centripetal acceleration is inversely proportional to the radius.
This lesson is a physics application of PocketLab that allows students to determine the radius of curvature of a gradual turn on a street. A PocketLab mounted on the dashboard of a car records both the angular velocity and the centripetal acceleration of the car as it moves at a nearly constant speed around the curve. All of the required data for an example problem are contained in files attached to this lesson. Alternately, students can collect their own data. If the latter approach is used, students should be cautioned to be safe: (1) follow all speed limits and traffic laws, and (2)
Yes, that's right--the physics of a falling and unrolling toilet paper roll. This experiment will give students practice in rotational motion of an object and translational motion of its center-of-mass. It will also involve both the kinematics and dynamics of the motion. While it can be done by use of the VelocityLab app, interpretation of the angular velocity data from the PocketLab app is much easier.
Rolling resistance is a force that opposes the motion when an object rolls along a surface. In this experiment a coasting cylinder on a carpet gradually slows down and stops due to rolling resistance. The primary factor affecting rolling resistance here is deformation of the carpet as the cylinder rolls. Not all of the energy needed to deform the carpet is recovered when the pressure from the cylinder is removed. In other words, the effect is non-elastic. The purpose of this experiment is two-fold: (1) to determine the force of rolling resistance and (2) to determine the coefficient o
This investigation shows how VelocityLab allows for a quick and easy demonstration of damped harmonic motion. The photo below shows the experiment setup as performed by the author. A jellied cranberry sauce can was selected as there is virtually no sloshing of the cranberry sauce as the can oscillates back-and-forth on a curved piece of laminate flooring. The center of the flooring is clamped down to the table with an adjustable wrench. The ends of the laminate flooring are raised a little with some small wood blocks. The cranberry sauce can is shown at rest at the VelocityLab zero pos
This experiment is designed for AP Physics and college physics students. It considers a solid cylinder of mass M and radius R that is rolling down an incline with a height h without slipping. Using energy and dynamics concepts, students first derive equations for (1) the speed of the center of mass of the cylinder upon reaching the bottom of the incline, and (2) the acceleration of the center of mass of the cylinder as it rolls down the incline. The free-body diagram at the center shows all forces acting on the cylinder as it rolls down the incline.
The yo-yo, a toy with an axle connected to two disks and string wound on the axle, has been of fascination to many for centuries. It also offers a perfect opportunity to study angular velocity when a PocketLab has been attached to it. A graph of angular velocity vs. time of a yo-yo will require students to think carefully about the detailed behavior related to its motion.
You don't need an expensive air track to do a quantitative study of momentum, impulse, and force involved in the collision of two carts. You can get very good results by the use of two PocketLabs, two iPhones, and a pair of carts from the PocketLab Maker Kit.