TODAY'S LESSON : DYNAMICS OF PARTICLE

assalamualaikum .

ini lah yang kami belajar semasa kelas petang tadi .

1.A force is a pull on a small object resulting from the interaction with another object .

2.Newton's first law

Lex I: Corpus omne perseverare in statu suo quiescendi vel movendi uniformiter in directum, nisi quatenus a viribus impressis cogitur statum illum mutare.

Law I: Every body persists in its state of being at rest or of moving uniformly straight forward, except insofar as it is compelled to change its state by force impressed.

This law states that if the resultant force (the vector sum of all forces acting on an object) is zero, then the velocity of the object is constant. Mathematically stated:

Consequently:

• An object that is at rest will stay at rest unless an unbalanced force acts upon it.
• An object that is in motion will not change its velocity unless an unbalanced force acts upon it.

Newton placed the first law of motion to establish frames of reference for which the other laws are applicable. The first law of motion postulates the existence of at least one frame of reference called a Newtonian or inertial reference frame, relative to which the motion of a particle not subject to forces is a straight line at a constant speed. Newton's first law is often referred to as the law of inertia. Thus, a condition necessary for the uniform motion of a particle relative to an inertial reference frame is that the total net force acting on it is zero.

example .

1. What will happen to an object at rest if no force is applied?

2. What will happen to an object at rest if it is pushed, but there is a large frictional force acting on the object?

3. What will happen to the motion of an object that is pushed, and there is very little frictional force acting on the object?

4. What will happen to the motion of an object if there is a constant net force applied to it?

answers :

-nothing
-depends on the frictional force
-an object that has a force applied to it temporarily (a push) will travel at a constant speed infinitely until an outside force disrupts it such as friction. under most circumstances where friction is present an object will slowly decelerate and eventually stop
-if a constant net force is applied to an object, it will accelerate at a uniform rate until the force is removed. example: if you drop an object it will constantly accelerate downward due to the constant force of gravity pulling down on the object. the net force is always the same, yet the objects speed keeps increasing

THAT'S ALL .

THANK YOU . =)