Abstract
This lab was to understand Newton’s second law F=ma. Two sets of experiments were
performed, first one the mass of the weight hanging varied, the second one the mass of the cart
varied. The result from the first experiment agrees with Newton’s second law and there was a
positive relationship between the mass of the weights and the acceleration of the cart. The second
experiment showed strange data, which could be due to experimental error.
Introduction
Newton’s second law describe that acceleration is produced when net force is applied on
a mass (F=ma). The acceleration is directly proportional to the net force, and it is in the same
direction as the net force. As the mass increase, the greater amount of the force is needed
(GSU,2017). Newton’s second law is applicable to everyday life, such as how to measure the
force of the car after a car accident. It can also be used in rocket science for the scientist to
calculate how much fuel is needed to launch the rockets (The Physics Classroom, 2017). The
gravitational force of an object is based on the mass of the object. As the mass of the object
increase, the gravitational force of that object increase (University of Arizona, 2017).
The purpose of this lab is to find out relationship between mass, acceleration and force
therefore understanding Newton’s second law F=ma. The hypothesis: 1) as the mass of the
weight increase, the acceleration will increase; 2) as the weight of the cart increase, the
acceleration of the cart will increase.
Materials and Methods
Materials:
Cart
String
Set of weights
In the first experiment, the weight of the cart is controlled and the variable was different
weight that was hung on the string.
In the second experiment, the weight that was hung on the string was controlled, and the
variable was the different weight of the cart (by adding the different weight onto the cart).
Procedures
At first, the cart was placed on a pathway, and one end of the cart has a string attach to it.
The other end of the string was placed on a pulley and fall naturally.
In the first experiment, the cart was placed at the end of the pathway away from the
pulley. While holding the cart still, different weights were placed at the end of the string, and the
cart was released. Data was collected by the motion detector.
In the second experiment, the cart was placed at the end of pathway away from the pulley.
While holding the cart still, different weights were placed on the cart, and nothing was attached
at the end of the string. Then the cart was released, and data was collected by the motion detector.
Motion detector
Pulley
Pathway
Data:
Results
Conclusion
Based on data in Table 1. and Graph 1., the relationship between mass and acceleration
was obvious, and as the mass increases, the average acceleration increases. Based on data in
Table 2. and Graph 2., there was no clear relationship between mass and acceleration was
undefined, and the graph had a W shape which does not allow a linear trend line that match with
the graph.
In our first experiment, Newton’s Second Law was confirmed, and that the acceleration
and the mass was positively related. This make sense because when the mass was added, the
gravitational force of the mass is larger, which gives a larger force to pull the cart. Since the
mass of the cart remain the same, the acceleration of the cart will increase.
In our second experiment, Newton’s Second Law was not confirmed. As the mass added
to the cart increases, the gravitational force of the cart increases, which hinders the movement of
the cart therefore should decrease the acceleration of the cart. However, this relationship was not
showed in our experiment. This could be due to some experimental error such as not setting up
the experiment correctly.
Improvement recommended