Pendulums are also used in scientific instruments such as accelerometers and seismometers. Historically they were used as gravimeters to measure the acceleration of gravity in geo-physical surveys, and even as a standard of length.
Types of pendulum .
1) simple pendulum
2) Foucault pendulum
3) Double pendulum
4) Conical pendulum
5) Compound pendulum
6) Torison pendulum clock
7) spring pendulum
8) Harmonograph
9) cycloidal pendulum
10) kapitza's pendulum
11) Furuta pendulum
12) Double inverted pendulum
13) Inertia wheel pendulum
14) Gridiron pendulum
15) Bob
16) Seconds pendulum
17) Barton's pendulum
18) Karter's Pendulum .