Understanding Acceleration Direction in a Pendulum Swing

  • Thread starter Thread starter ScullyX51
  • Start date Start date
  • Tags Tags
    Pendulum Vectors
AI Thread Summary
The discussion focuses on understanding the direction of acceleration in a pendulum swing, emphasizing that acceleration is related to the change in velocity rather than its direction. Participants clarify that "vector A" refers to acceleration, which can be analyzed at various positions of the pendulum. The acceleration direction varies as the pendulum moves through its arc, and can be determined using geometric methods involving angles. There is a consensus that visualizing the problem with a triangle can help in understanding the relationship between velocity and acceleration. Overall, the conversation aims to clarify the concept of acceleration in circular motion.
ScullyX51
Messages
35
Reaction score
0

Homework Statement


To understand that the direction of acceleration is in the direction of the change of the velocity, which is unrelated to the direction of the velocity.
The pendulum shown makes a full swing from -pi/4 to + pi/4. Ignore friction and assume that the string is massless. The eight labeled arrows represent directions to be referred to when answering the following questions.
What is the direction of vector A when the pendulum is at position 1?
What is the direction of vector A at the moment the pendulum passes position 2?What is the direction of vector A when the pendulum reaches position 3?



Homework Equations


I have no idea what equations I should be using here...I am very stuck and could use some hints to steer me in the right direction.


The Attempt at a Solution


All I know so far is that the acceleration is equal to the instantaneous rate of change in velocity.
 

Attachments

  • 6813.jpg
    6813.jpg
    6.4 KB · Views: 737
Physics news on Phys.org
Hi ScullyX51! :smile:
ScullyX51 said:
What is the direction of vector A …

I'm really confused …

is "vector A" the A in the picture, or is it the acceleration? :confused:
 
yes. I was very confused by that as well...but I am pretty sure vector a is referring to acceleration.
 
ScullyX51 said:
yes. I was very confused by that as well...but I am pretty sure vector a is referring to acceleration.

ok … then the question is asking where the acceleration is when something moves in a circle.

You can work this out using r and θ, or i and j, or just by drawing a little triangle where two sides are the velocities at angles θ and θ + dθ, and the third side is the change in velocity. :smile:
 
Thank you! :smile:
 
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .

Similar threads

Replies
9
Views
2K
Replies
20
Views
2K
Replies
15
Views
1K
Replies
14
Views
1K
Replies
27
Views
2K
Replies
16
Views
2K
Replies
1
Views
812
Back
Top