FORCES AND MOTION

FORCES AND MOTIONCHAPTER 22.3 Understanding InertiaLearning Outcomes: In the end of the class, student should be able to: explain what inertia is relate mass to inertia give examples of situations involving inertia

Inertia The inertia of an object is the tendency of the object to remain at rest or, if moving, to continue its uniform motion in a straight line unless acted upon by an external force. (Newtons Fist Law)

Inertia Objects tend to "keep on doing what they're doing."

Relationship between inertia and mass

Which trolley is more easier to start?Which trolley is more difficult to stop?The larger the mass, the larger its inertia

The larger mass have the tendency to remain its situation either at rest or in moving. Relationship between inertia and mass

Effects of InertiaPOSITIVE NEGATIVE Drying off an umbrella by moving and stopping it quickly.During a road accident, passengers are thrust forward when theircar is suddenly stopped.Building a floating drilling rig that has a big mass in order to be stable and safe.Passengers are hurled backwards when the vehicle starts to move and are hurledforward when it stops immediately.To tight the loose hammerA person with a heavier/larger body will find it move difficult to stop his movement.A heavier vehicle will take a long time to stop.2.4 Analysing MomentumLearning Outcomes: In the end of the class, student should be able to: define momentum of an object state the principle of conservation of linear momentum solve problems involving linear momentum

Momentum Momentum is defined as the product of its mass and its velocityp = mvUnit : kgms

Conservation of Momentum

The Principle of Conservation of Momentum In the absence of an external force, the total momentum of a system remains unchanged.

Applications of Conservation of Momentum

The squids uses it to propel itself in the water. The squid moves forward by discharging a jet of water from its body. An equal an opposite momentum created thus propels the squid in the opposite direction.

Elastic collision The colliding objects move separately after collision.

Inelastic collision The colliding objects move together after collision.

Explosion The objects involved are in contact with each other before explosion andare separated after the explosion.