How Does Elevator Motion Affect Pendulum Period?

  • Thread starter Thread starter sheepy
  • Start date Start date
  • Tags Tags
    Elevator Pendulum
Click For Summary
SUMMARY

The motion of a pendulum in an accelerating elevator is influenced by the change in effective gravitational force. When the elevator accelerates upward, the apparent gravitational acceleration increases due to the addition of inertial force, resulting in a modified period of the pendulum. The formula for the period of a pendulum, T = 2π(√(L/g)), indicates that as g increases, the period T decreases. Thus, the period of the pendulum shortens when the elevator moves upward with constant acceleration.

PREREQUISITES
  • Understanding of pendulum mechanics and the formula for period calculation
  • Familiarity with concepts of gravitational force and inertial force
  • Basic knowledge of non-inertial reference frames
  • Awareness of Foucault pendulum and its applications in demonstrating Earth's rotation
NEXT STEPS
  • Study the effects of acceleration on gravitational force in non-inertial frames
  • Explore the mathematical derivation of pendulum motion under varying gravitational conditions
  • Investigate the principles behind the Foucault pendulum and its significance in physics
  • Learn about the applications of pendulum motion in real-world scenarios, such as clocks and seismology
USEFUL FOR

Students of physics, educators teaching mechanics, and anyone interested in the dynamics of pendulum motion in varying gravitational environments.

sheepy
Messages
10
Reaction score
0

Homework Statement


A pendulum of length L is suspended from the ceiling of an elevator. When the elevator is at rest the period of the pendulum is T. How does the period of the pendulum change when the elevator moves upward with constant acceleration? Explain.

Homework Equations



T=2pi (\sqrt{l/g})

The Attempt at a Solution


i know that..the period relies on the gravitational force which changes as the elevator is moving. i THINK that when the elevator moves up, gravity increases..but i am not sure why. please help!
 
Physics news on Phys.org
If you are sitting in the bus and bus suddenly starts, you were thrown in the opposite direction. If you are sitting in the moving bus and if the driver suddenly applies the brakes you were thrown in the forward direction. Why is it so? Same reason applies to the lift problem.
 
I believe it is due to a thing called the "inertial force", it is an apparent force acting on the object when it is inside a non-inertial reference frame (such as the accelerating elevator)
this is the prime reason why the "Foucault pendulum" can be used to test whether the Earth is rotating.
 
sheepy said:
i know that..the period relies on the gravitational force which changes as the elevator is moving. i THINK that when the elevator moves up, gravity increases..but i am not sure why. please help!

On all objects in the frame of reference of the lift, there acts the pseudo force or the inertial force -ma, opposite to the direction of a. It's as if there's an added g-field of strength a, acting downward, in addition to the actual g.

Can you find T now?
 

Similar threads

  • · Replies 14 ·
Replies
14
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 7 ·
Replies
7
Views
4K
  • · Replies 20 ·
Replies
20
Views
2K
  • · Replies 3 ·
Replies
3
Views
1K
Replies
25
Views
7K
  • · Replies 27 ·
Replies
27
Views
2K
Replies
3
Views
2K
Replies
11
Views
5K