A simple pendulum sinks in water. The density of water is 1000kgm-3. The density of the bob is 1500kgm-3. The effective length of the pendulum is 1m. Gravitational acceleration is 9.8ms-2. What is the period of the pendulum? Neglect viscosity.

i can measure the period in the air or free place.but how can i measure the friction of water?

It says neglect viscosity. What other effect does submerging an object have?

upward buoyant force

It says neglect viscosity. What other effect does submerging an object have?

 

 

+1

 

 

toki

upward buoyant force

 

 

Which affects what parameter in the formula for the period of a pendulum?

Edited December 30, 20159 yr by studiot

 

 

+1

 

 

 

Which affects what parameter in the formula for the period of a pendulum?

in the formula T=2pi*root of L/g

there is nothing to effect it with out L and g

but as far as i know pendulam works in free place.but there is water here

but you are right that the upward byuiant force affects the g.because if the bob gets a force F=mg in free place ,in water it will get a force F-f(upward force)

Firstly a small correction

 

 

pendulam

 

The word is spelled pendulum

 

Yes you are right the period of the pendulum is equal to 2pi root (l/g). Note the brackets I have added to make the formula clear and correct.

 

However the acceleration term is not g when there are additional forces involved.

Remember acceleration = net force / mass

The mass has not changed but the net force has changed due to the additional bouyancy force which acts to reduce the gravitational force (weight) and therefore the acceleration.

So the pendulum swings mores slowly under water.

 

Here is a record of a practical experiment and explanation.

 

http://www.millersville.edu/physics/experiments/038/index.php