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.
There is a well-known problem in rotational dynamics that involves a meter stick. The meter stick is held in a vertical position with one end on the floor. It is then released so that it falls to the floor. The end initially on the floor is not allowed to slip during the fall. Students are asked to derive an equation that predicts the angular velocity of the meter stick just before it hits the floor. The derivation involves many physics concepts including gravitational potential energy, rotational kinetic energy, conservation of energy, moment of inertia, and angular velocity, thus giv
In this lesson students will find that a current-carrying loop can be regarded as a magnetic dipole, as it generates a magnetic field for points on its axis. The figure below shows a diagram and the equation for the magnetic field B. Derivation of this equation requries knowledge of the Biot-Savart Law, calculus and trigonometry. But in this lesson we are interested only in comparing experimental results from PocketLab's magnetometer to the theoretical equation in the figure below. More advanced students can consider derivation of the equation, if they wish.
These coils come in pairs with the same number of windings of wire on each of the two coils. In "true Helmholtz" configuration: (1) the coils are wired in series with identical currents in the same direction in each coil, and (2) the coils are placed a distance apart that is equal to the radius of each coil. When in this configuration, they produce a very uniform magnetic field that is directed along their common central axis.
Most everyone has spun a coin on its edge on a table top, and many find the result quite fascinating. The coin gradually begins to fall on its side while spinning, makes a whirring sound with increasing frequency the longer it spins, and then abruptly stops. The Swiss physicist, Leonhard Euler, studied this back in the 1700's. An educational toy, referred to as Euler's disk can now be purchased on-line and in hobby shops specializing in science. Such disks have been carefully engineered to spin for a much longer time than a coin.
An accelerometer is a device that will measure acceleration forces. These forces may be static, like the constant force of gravity pulling us towards the Earth’s surface, or the force may be dynamic, like an object moving or vibrating. This lab will show how to use to accelerometer to measure the static angle of a ramp as it rotates between 0° and 90°.
The moment of inertia (MOI) is the rotational inertia of an object as it rotates about a specific axis. Moment of inertia determines the torque required for a specific angular rotation about an axis. The moment of inertia depends upon the distribution of mass of the rotating object in relation to the axis the object is rotating about.