Pendulums What is a Pendulum The definition of

Pendulums

What is a Pendulum? • The definition of a simple pendulum is: a mass (BOB) suspended from a fixed point so that it swings Using this definition, is freely back and forth a yo-yo a pendulum? under the influence of gravity.

How do Pendulums move? • Pendulums use energy. • There are two categories of energy. POTENTIAL (stored) Maximum potential energy Maximum kinetic energy KINETIC(moving) Maximum potential energy

Pendulums experience friction while moving through the air. Friction caused the pendulum to slow down and eventually stop.

What are the variables that might affect the motion of a pendulum? Variable: part of the experiment that is changed What can you change about a pendulum?

Pendulum Variables Length of the string Mass of BOB Amplitude 15 g 50 g 25 g 15 g

What can be measured on a pendulum? • Periodic motion: a repeated and regular pattern of motion • Can you think of other systems that have periodic motion?

What is a cycle? • A cycle is: two swings, once back and forth

What is the frequency of a pendulum? • The rate at which repeated motion takes place • Stated as # of cycles per time So say… _____ cycles per _______ (number) (time)

How to calculate frequency… • A pendulum completes 50 cycles in 1 minute 50 1 _____ cycles per _______ minute (number) (time)

How to calculate frequency… • A pendulum completes 1 cycle in 30 seconds 1 30 seconds _____ cycle per _______ (number) (time)

Pendulum Variables Only one of the three variables affects the frequency of a pendulum Length of the Mass of BOB Amplitude string 15 g 50 g 25 g 15 g

Writing a hypothesis Independent variable: -Mass - Length of string - Amplitude Dependent variable: -frequency of a pendulum I hypothesize that when the ____________ (independent variable) changes the ____________ (dependant variable) will be affected.

Getting Started on the Lab • Set up your pendulum. • Read all lab directions. • Read the data table to know how to set up all materials. MASS (BOB) # OF WASHERS 1 STRING LENGTH (CM) 30 AMPLITUDE (DEGREES) 90°