Simple harmonic motion in a rocket?

Click For Summary

Homework Help Overview

The discussion revolves around the behavior of a simple pendulum suspended in a rocket ship under various conditions, specifically focusing on how different scenarios affect the period of oscillation. The context includes gravitational effects and motion dynamics in a uniform gravitational field near Earth.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants explore the effects of upward acceleration, freefall, constant velocity, mass changes, and length changes on the pendulum's period. There are attempts to analyze the implications of these conditions based on the fundamental equation for the period of a pendulum.

Discussion Status

Several participants have provided insights and reasoning regarding the effects of acceleration and mass on the pendulum's period. There is a mix of confidence and uncertainty in the answers proposed, with some participants questioning their own interpretations and others affirming the reasoning of their peers.

Contextual Notes

Participants are grappling with the implications of gravitational changes due to acceleration and the role of restoring forces in simple harmonic motion. The discussion reflects a variety of interpretations and assumptions about the physical principles involved.

PhysicsPhun
Messages
55
Reaction score
0
A simple pendulum suspended in a rocket ship has a period T0. Assume that the rocket ship is near the Earth in a uniform gravitational field. (If A and E are true, and the others are not, enter TFFFT).

A) If the ship accelerates upward, the period decreases.
B) If the ship goes into freefall, accelerating downward at 9.81 m/s2, the pendulum will no longer oscillate.
C) If the ship moves upward with a constant velocity, the period decreases.
D) If the mass of the pendulum doubles, the period increases.
E) If the length of the pendulum is doubled, the new period will be the square root of two times T0.

I thought I had the answer on this one. But I didn't..

My instinct was
A)F
B)F
C)T
D)F
E)T

I also tried, TTTFT, TFTFT and FTTFT (ABCDE)

As you can see I was very confident that C=T D=F E=T.. And I was wrong.

Anyone have a better idea?
 
Physics news on Phys.org
So what i think now is XXFFT

Really not sure on the first two, but i think that C=F D=F E=T
 
I'm most probably wrong but I think the answer is given to you at the beginning there.
So far I've come up with TFFFT.
When the ship accelerates upwards won't that increase the value of the downward acceleration due to gravity? So according to the equation
T=sqrt(l/g) (basic equation) wouldn't it cause the period to decrease.
And with the last one I'm think I'm sure (haha) that it is right because if you do the maths it works out as square root of 2 times T0.
I'm pretty sure that the second one is false.
The third one is false as well I think, because if velocity is constant then acceleration is 0. So nothing will happen to the period.
As for D, increasing the mass would decrease the period most likely.
Hope that helps you ;)
 
K...you guys...remember this equation for the period of a pendulum when solving...

T = 2(pi) * (length/g) ^ (1/2)...that means that when...

g increases...the period decreases...
...accelerating upwards means that g will be increased on the ship...moving upwards at a constant velocity has NO EFFECT whatsoever on g...I believe that the correct answers are...
A. T (Yes...accelerating upwards will increase g...thus decreases T)
B. T (yes...SHM requires a restoring forces...if the pedulum is in free fall...there is NO restoring force...)
C. F (no...when it is moving at a constant velocity...the value of g is not affected)
D. F (no..the mass of a pendulum as no effect on its period...as you can see from the equation)
E. T (yes...the equation proves this to be the case)
 
Cool thanks for the info on the restoring force man ;)
 
Thanks a lot for the explanations, you were right on :)
 
np man...anytime :-)
 

Similar threads

  • · Replies 51 ·
2
Replies
51
Views
5K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 42 ·
2
Replies
42
Views
7K
  • · Replies 13 ·
Replies
13
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
Replies
7
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
Replies
5
Views
2K
  • · Replies 9 ·
Replies
9
Views
3K