Institute for Studies in Theoretical Physics and Mathematics (IPM)
Physics
PHY 1000

Spring 2015
Frictional Forces
Weve been discussing forces on objects who have surfaces in contact. The
Normal Force is perpendicular to the surface.
There is another force due to surfaces in contact in which the force is parallel to
the surface. This is call the Fric
Institute for Studies in Theoretical Physics and Mathematics (IPM)
Physics
PHY 1000

Spring 2015
Applications of Newton's Law
Problem 1
In Figure, a cord pulls on a box of biscuits up a
long a frictionless plane inclined at = 30o. The
box has mass m = 5.00 kg, and the force from the
cord has magnitude T = 25.0 N. What is the box's
acceleration compon
Institute for Studies in Theoretical Physics and Mathematics (IPM)
Physics
PHY 1000

Spring 2015
Free Fall
Prof. J C N Rajendra
1
Free Fall
All objects moving under the influence of only gravity
are said to be in free fall
All objects falling near the earths surface fall with a
constant acceleration
This acceleration is called the acceleration due
Institute for Studies in Theoretical Physics and Mathematics (IPM)
Physics
PHY 1000

Spring 2015
Projectile Motion
1
Projectile Motion
An object may move in both the x and y directions
simultaneously (i.e. in two dimensions)
The form of two dimensional motion we will deal with
is called projectile motion
We may:
ignore air friction
ignore the ro
Institute for Studies in Theoretical Physics and Mathematics (IPM)
Physics
PHY 1000

Spring 2015
Forces and Newtons Laws
In the previous classes we used the concepts of displacement, velocity, and
acceleration to study the motion of objects.
Now we want to know how the object moves and why it moves, or, just as
importantly, why an object doesnt move?
Institute for Studies in Theoretical Physics and Mathematics (IPM)
Physics
PHY 1000

Spring 2015
Mathematics Review
18 January 2015
Prof. J C N Rajendra
1
Exponents
Algebraic symbols can be raised to a power
x
n
Exponent number
Base number
Eg: 34
Eg: 34 = 3 x 3 x 3 x 3 = 81
18 January 2015
Prof. J C N Rajendra
2
Exponents
Note:
x0
1
x
x2
x
3
18 Janua
Institute for Studies in Theoretical Physics and Mathematics (IPM)
Physics
PHY 1000

Spring 2015
Significant Figure
25 January 2015
Prof. J C N Rajendra
1
Significant Figure
Significant Figure
The number of meaningful digits in a number is called
the number of signicant gures or signicant digits.
Eg.
If we say that the distance from here to Dehiwela
Institute for Studies in Theoretical Physics and Mathematics (IPM)
Physics
PHY 1000

Spring 2015
Units, Dimensions and Conversions
18 January 2015
Prof. J C N Rajendra
1
Measurements
Like all other sciences, physics is based on
experimental observations and quantitative
measurements.
To describe natural phenomena, we must make
measurements of various