Introduction
Newton's Second Law of motion asserts that the acceleration of an object exhibits a direct proportional relationship with the subsequent force acting on it. It explores the relationship that exists between force, mass and acceleration as exhibited by an object. This experiment examines Newton's Second Law of motion by enabling a dwindling weight to speed up a glider of recognised quantity along a track. A thread that links the dwindling mass to the glider is passed above a smart pulley (Knight, 2004). It is imperative to note that the smart pulley exhibits insignificant inertia, low friction and its revolution is observed via a linked photogate. The photogate is linked to a computer which can monitor the movement of any object attached to the smart pulley.
Theory
For this section, the student should employ the use of a glider of mass M on an air track with insignificant friction. The glider will be attacked to a small metal disc m through the use of a string that is passed over the pulley. It is imperative to note that a descending force is exerted on the small mass by gravity. The downward force exerted on the mass is equivalent in size to its weight, mg. The entire system of mass M+m is made to accelerate by the gravitational force. As a consequence, Network’s Second Low of motion can be described as;
Mg= (M+m) a
The gravitational force acting on the object is mg, which is equivalent to the magnitude of the object’s weight. It is imperative to consider a free body diagram for each of the two masses, the glider and the falling weight. The forces acting on the small mass m includes the tension T and its weight as a result of gravity (mg). The tension force acts upwards while the force due to the weight of the object acts downwards. The resultant force causes the mass m to accelerate downwards;
(mg- T)= ma
On the other hand, there are three forces acting on the glider of mass M: the normal force N, its weight Mg, and the tension in the string. The normal force N acts on the glider of weight M in an upward direction while the Tension force acts rightwards and the force due to weight acts downwards. It is significant to note that there is no motion in the vertical direction.
Figure 1 describing the experimental set up of the frictionless system (Knight, 2004).
Therefore:
N= Mg and in the horizontal direction, T = Ma
Given that the small mass and the glider experience the same acceleration a, the two equations are added to obtain
mg=(M+m)a
Acceleration of the system is obtained as; a= mg/ (M+m)
Experimental Setup
The following materials and equipment will be used in this experiment; mass glider, smart pulley and picket fence, computer and Pasco interface, stopwatch, string, scale and weight set, air track. The experimental set-up encompasses of a mass glider positioned on an air track linked by a string passing over a smart pulley to a hanging load of weight mg and mass m. The glider and the load are regarded as a single object, subject to accelerating force mg (Knight, 2004). To demonstrate the proportional relationship that exists between the acceleration of the system and the accelerating force when the total mass is reserved constant, we start with a hanging load of mass m and gradually augment four similar metallic discs of mass m to the mass glider M. At this point, the accelerating force mg exerts a force on a system of overall mass M+5m. To increase the accelerating force by two, one metallic mass is relocated from the glider to the dangling load. The process is repeated while recording the relevant data. To triple the accelerating force, two metallic masses are relocated from the glider to the dangling load (Knight, 2004).
Procedure and Data Collection
Turn on the track and level it through adjusting the levelling screw in such a manner that any glider on the track does not possess any tendency to move in either direction. Position the glider at several various positions on the track to verify that it is leveled.
Switch on the computer and the signal interface. Insert the smart pulley into the interface while calling up the Data Studio. Select Smart Pulley from the list of the sensor and click on Position, Acceleration and Velocity from the list of Measurement.
After setting up the data collection interface, connect 5-gramm mass hanger to the glider using an estimate of 1.5 meters of string. Ensure that the string passes over the smart pulley so that the hanger accelerates a glider down the air track (Knight, 2004).
Use the scale to weigh each glider to acquire its mass and record the values in the data portion. Set one glider on the air track with the air track set off. The glider should be far from the pulley. Select Start and turn on the track to allow the glider to move and click Stop right before the hanger hits the floor.
Repeat this step with additional metallic discs transferred from the glider to the hanging load. Use the recorded data to draw a curve of the velocity of the glider against time and then determine the acceleration of the hanging load as well.
Results
Figure 2 A graph describing the relationship between force and acceleration (Knight, 2004).
References
Knight, R. D. (2004). Physics for scientists and engineers (Vol. 1). Pearson.
