Minggu, 16 Januari 2011

MANUSIA PEMBELAJAR

MENJADI MANUSIA PEMBELAJAR
Belajarlah bahwa tidak penting apa yang kita miliki,
Tetapi yang penting adalah siapa diri kita sebenarnya…
Belajarlah bahwa lingkungan dapat mempengaruhi pribadi kita,
Tetapi kita harus bisa bertanggung jawab untuk apa yang telah kita lakukan…
Belajarlah bahwa dua manusia dapat melihat hal-hal yang sama persis,
Tetapi terkadang mereka melihatnya dari sudut pandang yang berbeda…
Belajarlah bahwa bahwa kita tidak dapaat memaksa orang lain untuk mencintai kita,
Tetapi hanya dapat melakukan sesuatu untuk orang yang kita cintai…
Belajarlah bahwa tidak ada yang instan atau seba cepat di dunia ini,
Semuanya butuh proses dan pertumbuhan ,
Kecuali kita ingin sakit hati dan dikecewakan…

(Andrias Harefa, MENJADI MANUSIA PEMBELAJAR)

Sabtu, 08 Januari 2011

kinematika

Physics Chapter Kinematics (Motion Straight, Parabolic Motion and Circular Motion) High School Class XI

Name : Dwi Rahayu Widiyati
NIM : 1207053
Prodi : P. Physics (B) / VII

Dani riding a motorcycle across the street that has Trikora path length of 400 meters. He did not add and reduce the speed for 80 seconds. What is the speed of these bikes?
unknown: Δx = 400 m
Δt = 80 seconds
Asked: v ... ..?
Answer: v = Δx / Δt
= (400 meters) / (80 seconds)
=5 m / s
A motor bike across the street who has a long track 1000 m. The car does not increase and decrease the speed for 10 seconds. What is the speed of these bikes?
unknown: Δx = 1000 m
Δt = 10 seconds
Asked: v ... ..?
Answer: v = Δx / Δt
= (1000 meters) / (10 seconds)
= 100 m / s
Bari a distance of 30 m with a displacement of 10 m in 12 seconds. What is the average velocity bari?
unknown: Δx = 10 m
Δt = 12 seconds
Asked: vrata-rata ... ..?
Answer: vrata-rata = Δx / Δt
= (10 m) / (12 seconds)
= 5 / 6 m / s
Joang a distance of 30 m in 12 seconds. What is the average speed joang?
unknown: s = 30 m
Δt = 12 seconds
Asked: vaverage .....?

Reply: vAverage = s/Δt
=((30 m))/((12 seconds) )

= 2.5 m / s
A CD is playing, and turned out in 1 round takes four seconds. Then count the rotation frequency of the CD!
Given: T = 4 seconds
Asked: f …....?
Answer: f = 1 / T
= 1/(4 s)
= 0.25 Hz
From the question no 5 above, find the angular velocity of the cassette CD is playing!
Given: f = 0.25 Hz
Asked: ω ........?
Answer: ω = 2πf
= (2π rad) (0.25)
= 0.5 π rad / s
From the question above (No. 5 and 6), determine the central angle taken by the CD for 20 s!
Given: ω = 0.5 π rad / s
Asked: θ ... ... ... ... ..?
Answer: θ = ωt
= (0.5 π rad / s) (20 s)
= 10π rad
A charged particle moving in a circle with a speed point of the early 20 rad / s in the field elektostatis, until the particles get a slowdown 4 rad / s. Calculate the angular velocity when the particle stops for a moment, then move with speed in the opposite corner degan initial angular speed!
Angular velocity
ωt = 20 - 4T
0 = 20 - 4T
t = 5
So, after 5 seconds speed zero point, which means particles paused, then particles move to the opposite direction.
From the question no 8 above, calculate the angular velocity during 10 seconds!
Given: t = 10 s
ω = 20 rad / s
asked: ωt = 10 s ... ...?
replied: ωt = (20 rad / s) - (4 rad / s) (10s)
= -20 Rad / s
This means the same speed with the pace early, but the direction is different / opposite.
From the question above, look in seconds keberapa particle is at position zero central angle?
Given: θt = 20t - 2t ²
Asked: in seconds how many particles at the center point of zero?
Answer: θt = 20t - 2t ²
0 = 20t - 2t ²
t ² - 10T = 0
t (t - 10) = 0
t1 = 0 s or t2 = 10 s
So, after 10 s moves, the particles are at zero angle position, as at first.