Calculating force required to keep pendulum in motion

In summary, the conversation discusses the calculation of force required to keep a pendulum in motion. The force is believed to be equal to the frictional and dampening losses occurring during the oscillations. The initial force given to the pendulum is 3.5 kg and the displacement angle is 20 degrees. The length of the pendulum is 30 cm and its weight is 10 kg. The pendulum dies out after 40 cycles and the ultimate goal is to calculate the force needed to keep it in motion. The conversation also mentions the correct units for force (Newtons) and the use of a spring gauge for measurement.
  • #1
starcrossed
12
0
Hi,

I am interested in calculating the force required to keep a pendulum in motion. I believe This force will be same as the frictional loss + other dampening loss happening in the oscillations.

now,

I know the initial push or force that i am giving to the pendulum. let initial force given to pendulum be 3.5 Kg force-cm.

I also know the displacement angle of pendulum. The displacement angle A= 20 Degrees.

The length of the pendulum is L=30 cm. and the weight of the pendulum is W=10 Kg.

The pendulum oscillations dies out after say 40 cycles.

Can i calculate how much energy is lost in the pedulum during this 40 cycles?

How can i calculate the energy loss per cycle from this?

My ultimate aim is to calculate the force required to be given to the pendulum to keep it moving.


Can some one please help?

Thanks
 
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  • #2
starcrossed said:
I know the initial push or force that i am giving to the pendulum. let initial force given to pendulum be 3.5 Kg force-cm.

Force times distance (F dx) is work (energy), while force times time (F dt) is impulse or momentum transfer. Push is not a recognized term for either work or momentum transfer.

Force is measured in Newtons. Sometimes a Newton is called a kilogram-force, but it does not properly connotate the correct units.

1 Newton = 1 kilogram-meter / sec2
 
Last edited:
  • #3
sorry about that...my mistake,

I am actually pushing rather pulling the pendulum with 3.5 kgf force. i have a spring gauge which i am using for measurement. I lift the pendulum weighing 10 kg's to about 20 degrees. the spring gauge reads 3.5 kg. then i release the pendulum.

The time for one oscillation is about 1.4 seconds. the pendulum comes to rest in about 30 oscillations. the total time taken for it to come to rest is say around 40 seconds.

i am interested in find the amount of force that must be supplied to pendulum to keep it in motion.
 
  • #4
can some one please help?
 

1. How do you calculate the force required to keep a pendulum in motion?

The force required to keep a pendulum in motion is calculated using the formula F=mg sin(θ), where F is the force, m is the mass of the pendulum, g is the acceleration due to gravity, and θ is the angle the pendulum makes with the vertical. This formula is based on the concept of centripetal force, which keeps the pendulum moving in a circular motion.

2. What factors affect the force required to keep a pendulum in motion?

The force required to keep a pendulum in motion is affected by the mass of the pendulum, the length of the pendulum, and the angle at which it is released. A heavier pendulum will require more force to keep it in motion, while a longer pendulum will require less force. The angle at which the pendulum is released also affects the force required, with a larger angle requiring more force.

3. Can the force required to keep a pendulum in motion be calculated for any type of pendulum?

Yes, the formula for calculating the force required to keep a pendulum in motion applies to all types of pendulums, including simple pendulums, compound pendulums, and physical pendulums. However, the specific values used for mass, length, and angle may vary depending on the type of pendulum being studied.

4. How does the force required to keep a pendulum in motion change over time?

The force required to keep a pendulum in motion remains constant as long as the pendulum is in motion. However, as the pendulum swings back and forth, the angle at which it is released will change, causing the force required to also change. This is why pendulums eventually come to a stop, as the force required to keep them in motion decreases with each swing.

5. How is the force required to keep a pendulum in motion related to the period of the pendulum?

The period, or the time it takes for a pendulum to complete one full swing, is directly related to the force required to keep it in motion. This is because the period is affected by the length and mass of the pendulum, which are both factors in the force calculation. A longer pendulum with a greater mass will have a longer period and therefore require more force to keep it in motion.

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