Why doesn't mass of a pendulum effect its time period

In summary, the added energy from the mechanism allows the pendulum to keep swinging longer than if there was no added energy.
  • #1
Revin
3
0
I'll jump straight to my query.

If PE = mgh, and if the "m" is increased, the PE shall also increase.
Neglecting friction, Total mechanical energy(TME) = PE + KE.
Since PE increases, the total mechanical energy of the system shall also increase.
At its equilibrium position, where PE = 0, it should have a greater amount of KE since
KE = TME-PE.

Having more kinetic energy, it should hence have more velocity as well.
Hence, having more velocity, its time period should be shortened since it takes lesser time for it to complete one oscillation having the same distance ( Note that the value of h is not changed here).

After all this, why is it practically proven that mass doesn't effect the time period?
 
Physics news on Phys.org
  • #3
Revin said:
If PE = mgh, and if the "m" is increased, the PE shall also increase.
Neglecting friction, Total mechanical energy(TME) = PE + KE.
Since PE increases, the total mechanical energy of the system shall also increase.
At its equilibrium position, where PE = 0, it should have a greater amount of KE since
KE = TME-PE.
OK so far.
Revin said:
Having more kinetic energy, it should hence have more velocity as well.
No. Kinetic energy doesn't just depend on velocity, it depends on something else as well...
 
  • #4
All masses fall at the same rate.In effect your pendulum is a falling mass with just the right amount of added energy from the mechanism to overcome friction if it's in a clock so it does not stop.
If it's just a pendulum then it's a falling mass on a rope when it swings.
And all masses swing or fall at the same rate within a gravity field.
 
  • #5
Dear old Galileo sorted this out a long time ago. The story is that he won a bet about dropping masses off the Tower of Pisa. His contemporaries believed that a heavy object would reach the bottom before a light object - he knew better. That's just a story but is shows that reality is often counter-intuitive.
 

Related to Why doesn't mass of a pendulum effect its time period

1. Why doesn't the mass of a pendulum affect its time period?

The mass of a pendulum does not affect its time period because the time period of a pendulum is solely determined by its length and the acceleration due to gravity. This is known as the law of isochronism, which states that the period of a pendulum is independent of its mass.

2. How does the length of a pendulum affect its time period?

The length of a pendulum directly affects its time period. The longer the length of the pendulum, the longer it takes for the pendulum to complete one full swing. This is because a longer pendulum has a larger distance to travel and therefore takes more time to complete each swing.

3. Can the time period of a pendulum be affected by external factors?

Yes, the time period of a pendulum can be affected by external factors such as air resistance, friction, and temperature. These factors can cause the pendulum to lose energy and therefore have a shorter time period. However, in ideal conditions with minimal external factors, the time period of a pendulum remains constant.

4. Does the mass of the pendulum affect its speed?

No, the mass of the pendulum does not affect its speed. The speed of a pendulum is determined by the force of gravity and the length of the pendulum. The mass of the pendulum only affects the force needed to move the pendulum, not its speed.

5. Can a pendulum with a different mass have the same time period?

Yes, a pendulum with a different mass can have the same time period as long as the length of the pendulum remains the same. This is because the time period of a pendulum is determined by its length and the acceleration due to gravity, not its mass.

Similar threads

  • Mechanics
Replies
14
Views
3K
Replies
15
Views
1K
  • Classical Physics
2
Replies
36
Views
2K
  • Introductory Physics Homework Help
Replies
24
Views
1K
  • Introductory Physics Homework Help
Replies
10
Views
1K
Replies
3
Views
2K
  • Classical Physics
Replies
7
Views
1K
  • Introductory Physics Homework Help
Replies
2
Views
1K
  • Introductory Physics Homework Help
Replies
8
Views
1K
Back
Top