Find the acceleration due to gravity

In summary, the person shook a pendulum with a length of 3.6 meters and measured the time it took for it to swing from side to side. The time measured was 38 seconds. The acceleration due to gravity was found to be 9.4 meters/second squared.
  • #1
zade70
61
0

Homework Statement


A person shakes pendulum with length 3.6 meters. For 12 shakes he measured the time of 38 seconds. Find the acceleration due to gravity

Homework Equations


T=t/n
T=2*pi*sqrt(l/g)

The Attempt at a Solution


T(period)=t/n=3.167
T=2*pi*sqrt(l/g) l-length
g=4*(pi)^2*l/T^2
g=14.156
The solution in my book is 9.4 m/s^2. Where is my error?
 
Physics news on Phys.org
  • #2
Your solution method looks fine.

Perhaps there's an error in the book (Sometimes they update problems with new editions but fail to update the answer key), or there's something about the definition of "shakes" that we're missing. Is the problem statement a translation?
 
  • #3
gneill said:
Your solution method looks fine.

Perhaps there's an error in the book (Sometimes they update problems with new editions but fail to update the answer key), or there's something about the definition of "shakes" that we're missing. Is the problem statement a translation?
Yes
 
  • #4
What is the original language? Is there more information in the original problem statement that you haven't shown?
 
  • #5
gneill said:
What is the original language? Is there more information in the original problem statement that you haven't shown?
I have given all the information. The correct answer is 9.4 m/S^2
 
  • #6
Your answer is correct (if you round to the correct number of significant figures). I don't agree with the book's answer.
 
  • Like
Likes zade70
  • #7
Was the pendulum a simple pendulum (mass bob on a string) or something else, like a solid rod?
 
  • #9
zade70 said:
When we do similar problems we consider the pendulum like this http://dev.physicslab.org/img/14c7c356-6f6e-49e4-a953-2396343435fb.gif. The problem just says a pendulum is vibrated.
Okay, so simple pendulum it is:
upload_2016-3-23_13-12-2.png


Then again, I support your result and not the book's.
 
  • Like
Likes zade70
  • #10
Saloni Khanna said:
Saloni Khanna, post: 5419032, member: 588906"]
gneill said:
Okay, so simple pendulum it is:
View attachment 97843

Then again, I support your result and not the book's.
gneill, did you use paint to draw that picture or what program did you use, i really want to know . Sorry for saying something not related to OP
 
  • #11
The Vinh said:
gneill, did you use paint to draw that picture or what program did you use, i really want to know . Sorry for saying something not related to OP
The picture came from the OP's link. I just cut-and-pasted it to make it visible in-thread; off-site links have a tendency to disappear over time.

I do make quite a few images for posting here though. I use an old version of Visio to make them.
 
  • #12
gneill said:
The picture came from the OP's link. I just cut-and-pasted it to make it visible in-thread; off-site links have a tendency to disappear over time.

I do make quite a few images for posting here though. I use an old version of Visio to make them.
many thanks to you
 

FAQ: Find the acceleration due to gravity

1. What is the definition of acceleration due to gravity?

The acceleration due to gravity is the rate at which an object falls towards the Earth's surface due to the force of gravity. It is represented by the symbol "g" and has a value of approximately 9.8 meters per second squared (m/s²).

2. How is acceleration due to gravity calculated?

Acceleration due to gravity can be calculated using the equation g = G * (M / r²), where G is the universal gravitational constant (6.67 x 10^-11 N*m²/kg²), M is the mass of the Earth, and r is the distance between the object and the center of the Earth. This equation can also be simplified to g = 9.8 m/s² for objects near the Earth's surface.

3. Does acceleration due to gravity vary on different planets?

Yes, the acceleration due to gravity varies on different planets due to differences in mass and radius. For example, the acceleration due to gravity on Mars is approximately 3.7 m/s², while on Jupiter it is approximately 24.8 m/s².

4. How does the mass of an object affect its acceleration due to gravity?

The mass of an object does not affect its acceleration due to gravity. According to Newton's Law of Universal Gravitation, the force of gravity between two objects is directly proportional to their masses, but the acceleration due to gravity remains constant for all objects near the Earth's surface.

5. Can the acceleration due to gravity be negative?

Yes, the acceleration due to gravity can be negative. This occurs when an object is moving away from the Earth's surface, such as when it is thrown upwards or when it orbits the Earth. However, the magnitude of the acceleration due to gravity remains constant at 9.8 m/s².

Similar threads

Replies
20
Views
1K
Replies
14
Views
817
Replies
7
Views
3K
Replies
9
Views
1K
Replies
7
Views
1K
Replies
19
Views
1K
Replies
7
Views
1K
Replies
5
Views
2K
Replies
6
Views
501
Back
Top