Tiêu đề Notes_Force and Laws of Motion_Force and Laws of Motion.pdf ✅

FORCE & LAW’S OF MOTION INTRODUCRTION : From our day to day experience, we all are familiar with the concept of ‘Force’ While opening a door, lifting a bucket or a bag, kinetic a football or throwing a stone, we have to act differently and in many ways. We are either pushing or pulling the object. No non-living object moves on its own. We have to apply the effort in the form of push or pull. This pull or push is called force. Thus a force is an external agency that displaces or tends to displace a body from its position of rest. The direction in which the object is pushed or pulled is called the direction of the force. Force has both magnitude and direction. It is a vector quantity FROCE : Force is the ‘push’ or ‘pull’ which can make a body move, stop a moving body, change the direction and speed of a moving body UNITS OF FORCE The unit commonly used for measuring force is called kilogram force (Symbol kgf.) How big is the kilogram force ? It is the force required to vertically life a body a mass of 1 kg. In other words, the force of gravity acting on 1 kg mass is one kgf. However. For measuring smaller force. The unit is gram force (symbol gf). One gram force (lgf) is the force required to lift a mass of 1 g vertically As, 1 kg mass is equal to 1000 g. therefore 1 kgf = 1000 gf In SI system, the unit of force is called Newton (symbol N). It has been found that one kilogram force is equal to 10 newtons. Actually 1 kgf = 9.8 However, to simplify, it is taken as 10 N. a Thus , if was have to lift a mass of 1 kg vertically, the force required in the International system of units is10 N 10 N force is needed for lifting mass = 1 kg or 10 N force is needed for lifting mass = 1000 g 1 N force is needed for lifting mass = 100 g EFFET OF FORCE 1. EFFCT ON SHAPE Ex. 1
Ex.2 Ex.3 2. EFFECT ON MOTION & DIRECTION Ex.1 Ex.2 Ex.3
Ex.4 4. EFFECT ON SPEED KINDS OF FORCES 5. CONTACT OF NON-CONTCT FORCE : CONTACT FORCE : The force which act on a body either directly or through some connector are called contact forces. Example : Biological force, muscular force, mechanical forces and frictional forces are the example of contact forces. NON-CONTACT FORCE : The forces which do not make a direct contact with a body and act through space, without any connector are called non-contact forces. Example : (i) The force of gravity of the earth is non-contact force which attracts all bodies the earth (ii) The electrical force can pull tiny bits of dry paper is a non-contact force. (iii) A magnet can attract common pins of steel from a distance and hence the magnetic force is non-contact force
MUSSULAR FORCE This force produced by the muscles of living is called muscular force or biological force. MECHANICAL FORCE The forces generated by mechanes are called mechanical force