Evan's Space

Wonders of Physics

Pendulum: Displacement-time vs KE-time graphs

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Basic Concepts of the pendulum:
Refer to this post for the factors that affect the period of the pendulum



Factors that affect the period T of a pendulum

Period, T, is the time taken for one complete oscillation.

The period T of a pendulum is affected by the following factors.
1) the length of the pendulum:
– the longer the length, the longer the period (i.e. swing slower)

2) the gravitational field strength, g
– the greater the g, the shorter the period (i.e. swing faster)
(e.g. the g on earth is 10 N/kg while that on the moon is 1.6 N/kg, hence the period on           the moon will be longer)

NOTE: (common misconceptions)
Period, T, of the pendulum is NOT affected by
1) the angle of release (as long as the angle of release is between 10 to 15 degrees)
(if the angle of release is small, the swing will not be fast and air resistance will not be         significant)
2) the mass of the pendulum ball

Refer to the video below for the demonstration of the above concepts.

Pendulum: Displacement-time vs KE-time graphs
Click here to understand the concepts of Displacement-time vs Kinetic Energy-time graphs of a pendulum




Vector Diagram – Parallelogram Method

For Combined Science (Physics), drawing of vector diagram is a must.
In general, two known forces are given and the resultant force of these two forces is to be found using the vector diagram.

There are two methods to draw vector diagram 1) Parallelogram method and 2) Tip-to-tail method. In this post, the parallelogram method is used.

Example 01
Capture 01

Example 02

Capture 02

Example 03

Capture 03

Example 04

Capture 04

Click here to view another post on Closed-Loop Triangle Method (2 forces, 2 unknowns, 1 known)

Click here to view how parallelogram method is applied to various kind of questions

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Vernier caliper and Micrometer screw gauge

Vernier caliper and micrometer screw gauge are used to measure length.
Vernier caliper is used in general for measuring length between 0 to 15 cm.
Micrometer screw gauge is used in general for measuring length between 0 to 2.5 mm.
The accuracy (precision) of
– ruler (0.1 cm)
– vernier caliper (0.01 cm)
– micrometer screw gauge (0.01 mm)

<p><a href=”http://vimeo.com/117659706″>vernier caliper</a> from <a href=”http://vimeo.com/user7367248″>evantoh</a&gt; on <a href=”https://vimeo.com”>Vimeo</a&gt;.</p>

<p><a href=”http://vimeo.com/117667759″>micrometer</a&gt; from <a href=”http://vimeo.com/user7367248″>evantoh</a&gt; on <a href=”https://vimeo.com”>Vimeo</a&gt;.</p>