MOMENTUM IMPULSE COLLISIONMOMENTUM IMPULSE COLLISION

RESILIENCE PERFECT

RESILLIENCE PARTIALLY

RESILLIENCE NOT AT ALL

RESILIENCE PERFECT

RESILLIENCE PARTIALLY

RESILLIENCE NOT AT ALL

Basic Competencies

Learning Activities

indicator

Guide

Krisna SuryantiRSA1C314011

Assessment

Exercise

What is it ??

Momentum

Momentum is: the tendency of a moving object to continue moving at a constant speed, or the multiplication of mass with velocity object.formulated:P = m.v By: p = momentum (kg m / s)m = mass of the object (kg)v = velocity (m / s)

Basic Competencies

shows the relationship between the concept of impulse and momentum to solve the problem of collisions

LEARNING ACTIVITIES

• Discuss the concept of momentum, impulse, the relationship between impulse and momentum in class discussions• Experimenting law of conservation of momentum• Analyze the impact problem solving by using the law of conservation of momentum

indicator

• Formulating the concept of impulse and momentum, the relationship between them, and their application in life (eg rocket)• Formulate the law of conservation of momentum for a system without external forces• Integrating the law of conservation of energy and momentum conservation for many collision events

Assessment of performance (attitudes and practices), the written test

Assessment

Guide

Physics books relevantMaterials: worksheets, student reports, presentation materialsTools: dynamic wagon, sled, tiker timers, media presentations

Exercise

THE LAW OF CONSERVATION OF MOMENTUM

Two balls each having a mass m1 and m2, where m1 = m2. m1 m2 moving towards the stationary (v2 = 0). After the collision velocity turned into v1 'and v2'. When F12 is the style of m1 m2 used for mashing and F21 style of m2 used for mashing m1, then according to Newton's Third Law:

Total momentum of the object 1 and object 2 before and after the collision is equal / fixed. This law is called the Law of Conservation of Momentum.

What impulses relationship with Momentum?

One of Newton's law says that the force acting on an object is equal to the mass multiplication with the acceleration.

F = m.a.

If we enter into the formula I = F Δt

I = F. Δt

I = m.a (t2-t1)

I = m v / t (t2-t1)

I = m.v1 - mv2

"the magnitude of the impulse that works / worked on an object is equal to the change in the momentum of the object."

IMPULS

Impulse is defined as: the product of the force by the time required

by the force to moving .Impuls can be formulated:I = F. ∆ t

By: I = impulseF = force (N)Δt = time interval (s)

According to Newton's 2nd law:F = m aBy substituting the second equation is obtained

I = F Δt = mvt – mv0

with:MVt = momentum of the object, as the speed vtMV0 = mementum object when the velocity v0

Impulse as momentum changes

The concept of impulse and momentum changes can be viewed as a concept that arises from the application of Newton's second law , namely : (1.3)F ma

m

Play

Analisis Animasi

mF v1 m

v2

Animation : Stick provides a force ( F ) on the ball of mass ( m ) , then the ball velocity changes ( v = v1 - v2 ) in the interval ( t ) .

A change of pace on the object will give the average acceleration of :

2 1 (1.4)v v

at

The substitution of equation ( 1.4 ) to equation ( 1.3 ) , obtained

2 1

2 1 (1.5)

v vF m

t

F t m v v

Magnitude Ft called impulse , which means that the impulse is the change in momentum.

!Animasi

EXAMPLE

The working principle is the main rocket conservation of momentum . The number of rockets on the runway momentum equal to zero . When a rocket is launched , has sprayed down the burning of a high-speed jets of gas is made rocket moves upwards to compensate for the gas momentum .

The law of conservation of momentum on the rocket , namely :

Play

IND

ON

ES

IA

Animasi 9:

( ) ( )(1.15)R

mv mF v

t t

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1 1 2 2

1 1 2 2

0 ' '

' ' (1.14)

m v m v

m v m v

Impulse is the change in momentum(F t = p= (mv)):So, force rockets is :

Collision

The collision was an event meets two moving objects. When the collision apply the law of conservation of momentum but not always apply the law of conservation of kinetic energy. Maybe some kinetic energy is converted into thermal energy due to the collision.

Collision

A collision occurs when a moving object on another object that is stationary or moving too . For example , a billiard ball collision or collision between two cars on the highway .

A B

Play

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Animasi 4

The collision that occurs when the mass center point of the object toward the center of mass of the object point to another . As shown in the following animation .

amount of mechanical energy of the system ( objects that collide ) is not always fixed , likely after the collision energy turns into heat . However , the amount of momentum of the system is always fixed .

Perfectly elastic collision

Perfectly elastic collision is a collision between two objects remain the same amount of mechanical energy is great, just before and after the collision . In other words , perfectly elastic collision no energy is lost

Thus , the elastic perfectly valid : law of conservation of momentum law of conservation of mechanical energyFor example , two balls with the respective masses mA and mB , initially moving with velocity v1 and v2 . after the collision , the speed of the ball becomes v1 ' and v2 ' . Note animations

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v1 v2

►Bola sebelum tumbukan

Play

►Bola saat tumbukan

v2’ v1’►Bola sesudah tumbukan

►Perhatikan animasinya

Animasi 5

collision resilient portion

In the collision elastic portion only applies the Law of Conservation Momentum , while the Energy Conservation Law does not apply , because the kinetic energy after the collision smaller objects before the collision . It is caused when there is no collision energy into heat or sound energy .

1. Apply the law of conservation of momentum ' '

1 1 2 2 1 1 2 2m v m v m v m v

Feature collision resilient portion :

2. Do not apply the law of conservation of mechanical energy

3. The coefficient of restitution ( e ) valued at between zero and one : 0 1e

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lantai

Play

Animasi :

RESILLIENCE NOT AT ALL

Elastic collision not at all characterized by:1.Applicable law of conservation of

momentum.2.Not applicable law of conservation of

kinetic energy.3.Restitution coefficient of zero

The collision between two objects with no resilience at all , then after the collision of the two bodies will have the same speed ( v'1 = v'2 = v ' ) , because the coefficient of restitution equal to zero ( e = 0 ) Note animation 8 !

' '1 1 2 2 1 1 2 2m v m v m v m v

In general, the impact resilience is not at all apply the law of conservation of momentum

Because the speed of the two objects after the collision the same , namely :

Then the law of conservation of momentum equation , becomes :

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Play

Animasi :

1 2

v1 1 2v2

v'1 =v’2 =v’

' ' '1 2 (1.12)v v v

'1 1 2 2 1 2 (1.13)m v m v m m v