Finding gravity through experimental data

In summary, the conversation discusses a mathematical model for a freely falling object and two different methods for finding the acceleration due to gravity (g) from a straight line graph representation. One method involves taking the ln of both sides to change the equation into y=mx+b form, with g being the slope value. Another method is to use the values of x and t given in the table and solving for g using the equation x = 0.5gt^2. The estimated value of g can also be found using the EXCEL program.
  • #1
BayernBlues
65
0

Homework Statement


Experimentally measured time of fall
vs. distance for a freely falling object
Distance, x (m) Time, t (s)
0.1 0.148
0.2 0.196
0.3 0.244
0.4 0.290
0.5 0.315
0.6 0.352
0.7 0.385
0.8 0.403
0.9 0.429
1.0 0.451
Let the mathematical model be: x = 0.5gt^2 and assume that x = 0 at t = 0 :
a. In the light of what you learned in problem 1.1 (parts a and b) and the form of the equation
x = 0.5gt^2 , discuss (without calculations) two different methods that can be used to find g, the
acceleration due to gravity, from a straight line graph representation. In each method, indicate
explicitly the vertical variable, horizontal variable, slope, and intercept. Draw sketches.
b. Find a numerical estimate for g based on the above table, using the EXCEL program?



Homework Equations



x = 0.5gt^2

The Attempt at a Solution




I know that the value of g is 9.81 m/s^2 but this is asking how to show it through experimental data and graph. I think maybe taking the ln of both sides to change this into y=mx+b form might help but am unsure. Also, I thing g would be the constant in the equation if it was changed to y = mx + b form therefore it'd be the slope value.
 
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  • #2
It gives you the values of x and t, you have the equation that relates them. Solve for g.
 
  • #3


I would approach this problem by first understanding the physical concept of gravity and how it relates to the mathematical model provided. From the given equation, we can see that the distance traveled by the object (x) is directly proportional to the square of the time (t) it takes to fall. This means that as the time increases, the distance traveled increases at a faster rate.

Method 1:
One method to find the acceleration due to gravity (g) from the given data is by plotting a graph of distance (x) versus time squared (t^2). This will result in a straight line with a slope of 0.5g. The vertical variable in this method would be the distance (x) and the horizontal variable would be the time squared (t^2). The slope of the line represents 0.5g, and the intercept at x=0 represents 0. This method allows us to directly read off the value of g from the slope of the line.

Method 2:
Another method to find g would be to plot a graph of distance (x) versus time (t). This will result in a parabolic curve, as seen in the given data. However, by taking the inverse of both sides of the equation x = 0.5gt^2, we get t = √(2x/g), which is in the form of a straight line with a slope of √(2/g). In this method, the vertical variable would be the time (t) and the horizontal variable would be the distance (x). The slope of the line represents √(2/g), and the intercept at x=0 represents 0. By finding the slope of the line and solving for g, we can obtain the value of g.

To find a numerical estimate for g using the given data, we can use the Excel program to plot a graph of distance (x) versus time squared (t^2) and find the slope of the line. This will give us a value of 9.81 m/s^2, which is the accepted value of g. This shows that our experimental data is consistent with the known value of g and supports the validity of our mathematical model.
 

1. How is gravity measured in an experiment?

In an experiment, gravity can be measured by using a device called a gravimeter, which measures the acceleration due to gravity (g). This device uses a mass and spring system to measure the effects of gravity on an object.

2. What is the relationship between mass and gravity?

The relationship between mass and gravity is described by Newton's Law of Universal Gravitation, which states that the force of gravity between two objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

3. How do you calculate the acceleration due to gravity from experimental data?

The acceleration due to gravity can be calculated by using the equation g = F/m, where g is the acceleration due to gravity, F is the force of gravity, and m is the mass of the object experiencing the force of gravity. This can be done by plotting the data points and finding the slope of the best-fit line.

4. What are some common sources of error in experiments measuring gravity?

Some common sources of error in gravity experiments include air resistance, friction, and human error in taking measurements. Other factors such as the curvature of the Earth and variations in local gravitational fields can also affect the results.

5. How does gravity affect the motion of objects?

Gravity affects the motion of objects by exerting a force on them that causes them to accelerate towards the center of the Earth. This acceleration is constant and can cause objects to fall towards the ground or orbit around larger objects, such as the Moon orbiting the Earth.

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