Learning Scenarios Friction Sin

8/12/2019 Learning Scenarios Friction Sin

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LEARNING SCENARIOS

Teacher : Good evening, students. (Giving a friendly condition in learning

process)

Student : Good evening, Miss.

Teacher : Nice to meet all of you in healthy conditions. Well, before e start our

lesson today, let us !ray together. "ray began. (Students and teachers pray

together). "ray its over. #$ay student, no at the first % ill continue to

chec$ing your absent. &nyone absent today' (Giving a friendly condition

in learning process)

Student : No, Miss.

Teacher : (ight. Today e ill learn a ne cha!ter is about the friction force. The

!ur!ose of today)s lesson is that you be able to e*!lain the definition of

friction force, be able to $no the ty!es of friction force, using the

formula of friction force in flat surface to solve the !roblem, and the last

be able to $no the im!lication of friction force in daily life. +ut before

e start this lesson, are you guys ready for the lesson today'(concentration)

Student : es, Miss

Teacher : #$, before e e*!lain more dee!ly about that, % ill sho you about

the !henomenon in your daily life and an animation that relate to the

friction force. -et)s see in the slide. (Giving an example and ilustration)

Student : Student see the !henomenon in the slide seriously.

Teacher : #$, its about the !henomenon of friction force. No, ho can e*!lain,

hy the omen can be sli!!ed hen her as !lay ice s$ating'

(Understanding question, asking a relevant answers)

Student : %)m, Miss. %ts caused by the floor in the ice s$ating is sli!!ery.

Putu Sintya Pratiwi (1013021007) Page 1


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Teacher : "erfect. No, e com!are the ice s$ating !henomenon ith

!henomenon of someone al$s on as!halt roads that sho in the slide.

(concentration)


Teacher : No, ho can e*!lain, hich one is fluently hen e al$ing on

sli!!ery floors or as!halt roads' (Analytical question, asking a relevant

answers)

Student : % thin$ in the sli!!ery floors e ill al$ more fluently than on the

as!halt.

Teacher : Good. +ut hy this ha!!en' (Understanding question, asking a

student feedack)

Student : %ts because in the sli!!ery floor there is no friction.

Teacher : Good anser. Who can e*!lain the definition of friction force'

(Understanding question, asking a relevant answers)

Student : riction force is the force e*erted by a surface as an ob/ect moves

across it or ma$es an effort to move across it.

Teacher : Good. Who can com!lete your friends anser' (Giving the

opportunity to answer for others student and deployment)

Student : %)m sir, the friction force is the contact force beteen to surfaces

hich has the o!!osite direction ith the direction of ob/ect)s movement.

Teacher : 0orrect. No, let see on the slide again. % ill give you an animation of

the ty!es of friction force. (Giving an example and ilustration)


Teacher : #$e. There are the ty!es of friction force. &ccording to the animation

before, there are three im!ortant information to determine the friction

force of an ob/ect, namely:



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!" #b/ect is move, hen the a!!lied force is more than ma*imum

static friction 1F >fsmax). So, the friction force that act to the ob/ect

is $inetic friction force 1fk)"

#" The ob/ect is !ro!er to move, hen the a!!lied force is same as

ma*imum static friction 1F =fsmax).

$" #b/ect is doesnt move, hen the a!!lied force is less than

ma*imum static friction 1F < fsmax). (Giving the clarity and

emphassing the important concept)

2ntil this, ho not understand about that' (Ask for student views)

Student : Silent.

Teacher : +ecause all of you as silent, so % thin$ all of you understand about

that. -ets e continu to discuss about the friction force in flat surface.

The force that act on the ob/ect above is shon belo.

&ccording to the figure, the friction force is !ro!ortional ith the normal

force and coefficient of friction, mathematically it can be ritten as

%f = . Where f is the friction force 1N3, is the coefficient of static

friction, and then N is the normal force 1N3. The coefficient of friction

force is de!end to the characteristic beteen to ob/ect that been contact.

The formulas for ma*imum static friction and $inetic friction is same as

the general formula of friction force. +ut, the only difference being the

coefficient of friction alone, the coefficients of static and $inetic friction.


N

f


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&re you clearly about that' (Give an emphassing of the important

concept and giving a clarity)

Student : es, Miss.

Teacher : "erfect. %ts means that you are seriously to learn about the friction force.

#$e, no % ill give you a 4uestion to chec$ your understanding of

friction force. See in the slide.

&ne day 'ogar move a lock of mass ! kg" 'he eam was on the floor

with the "$ static coefficient of friction and kinetic friction coefficient of

"# on eam" f the lock is pulled with a force * % parallel to the floor,

please determine the frictional forces acting on the lock+

Who can anser the 4uestion in the front of the class' (hecking the

student feedack). % ill give a chocolate if you try to anser my 4uestion

in front of the class. (Giving a reinforcement)

Student : %)m, Miss. Student rite on the hite board.

5etermine the ma*imum static friction that act to the ob/ect.

fsma*6 s. N 6 s.

fsma*6 s. m.g 6 7,8 . 97.97 687 N

%t turns a!!lied force is smaller than the ma*imum static friction, the

frictional forces acting on the body is the force e*erted on the beam. So,

the friction force is e4ual to f 6 6 N and the ob/ect is doesn)t moving.

Teacher : ;*cellent. Who not understand about that' (Ask for student views)



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Student : Silent.

Teacher : eah. Silent is good. % thin$ you understand about that.

+efore e are closed this meeting, ho can conclude the matter that e

discussed today' (Asking student feedack)" %f you be able to conclude our

lesson today, % ill give you my last chocolate' (Giving a reinforcement)

Student : %)m, Miss. The conclussion are friction force is the force that resist the

motion of ob/ects, so the ob/ect is sto! moving. The amount of the

frictional force is affected by the rude or sli!!ery surfaces of each other.

The im!lication of the friction force namely, hen e $ic$ the ball, hn

riding the bi$e cycle, hen e al$ing on the road.

Teacher : eah, good. May be another conclussion again' (Giving the

opportunity to answer for others student and deployment)

Student : There are four ty!e of friction force, namely static, $inetic fs ma*, the ob/ect is doesn)t move.

Teacher : 0om!lete conclussion. #$e guys, !lease solve the !roblem !age ?7

number 9@ in your te*t boo$. 0ollect to me in ne*t ee$. No, before e

closed, lets !ray together again. "ray its begin. "ray its over. ;n/oy your

resting. Good evening. (Giving a evaluation as a homework)"

Student : Good evening, Miss.


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Learning Scenarios Friction Sin