Universitas FISIKA FISIKA DASAR DASAR

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FISIKA

DASAR

_DASAR

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Besaran dan satuan

Resnick dan Halliday, 1983, Fisika terjemahan P Silaban dan E Sucipto, Erlangga, Jakarta.

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III. Kinematika dan Dinamika Partikel

A)Gerak satu dimensi

B)Gerak dua dimensi

C)Hukum-hukum gerak

D)Gerak melingkar dan aplikasi lainnya

Kinematika : Membahas deskripsi gerak

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III.A. Gerak 1 dimensi

1 Displacement, Velocity and Speed

2 Instantaneous Velocity and Speed

3 Acceleration

4 One-Dimensional Motion with Constant Acceleration

5 Freely Falling Objects

1. Perpindahan, kecepatan dan kelajuan 2. Kecepataan sesaat dan kelajuan sesaat 3. Percepatan

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III.A.1

Displacement, Velocity and Speed

Perpindahan (besaran vektor): perubahan posisi

Kecepatan rata-rata (besaran vektor): Perpindahan dibagi rentang waktu selama terjadinya perpindahan tersebut.

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III.A.2.

Instantaneous Velocity and Speed

Instantaneous velocity _x equals the limiting value of the ratio

x/_t as t approaches zero

Note that the displacement x also approaches zero as t

approaches zero. As _x and _t become smaller and smaller, the ratio x/t approaches a value equal to the slope of the line

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In calculus notation, this limit is called the derivative of x with respect to t, written dx/dt:

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A particle moves along the x axis. Its x coordinate varies with time according to the expression where x is in meters and t

is in seconds. The position–time graph for this motion is shown in Figure below. Note that the particle moves in the negative x

direction for the first second of motion, is at rest at the moment t = 1 s, and moves in the positive x direction for

Sebuah pertikel bergerak sepanjang sumbu x. Koordinat x berubah terhadap waktu mengikuti persamaan x= -4t + 2t2_{, x dalam meter}

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III.A.3.

Acceleration

The average acceleration of the particle is defined as the change in velocity x divided by the time interval t during which that change

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The velocity of a particle moving along the x axis varies in time according to the expression , where t is in seconds.

(a) Find the average acceleration in the time interval t = 0 to t = 2.0 s.

Kecepatan sebuah partikel yang bergerak sepanjang sumbu x berubah terhadap waktu mengikuti

persamaan v=(40-5t2_{) m/s dengan t dalam sekon/detik.}

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Sebuah pesawat mendarat dengan kecepatan 63 m/s.

Berapakah percepatannya jika pesawat tsb berhenti dalam 2 detik?

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III.A.5.

Gerak jatuh bebas

Hanya dipengaruhi gaya gravitasi saja, tanpa memperhatikan gerak asalnya.

Benda yang dilempar keatas atau kebawah atau dilepaskan dari keadaan diam, mengalami percepatan gravitasi yang arahnya

kebawah (menuju pusat bumi) tanpa memperhatikan gerak asalnya.

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A stone thrown from the top of a building is given an initial velocity of 20.0 m/s straight upward. The building is 50.0 m high, and the stone just misses the edge of the roof on its way down, as shown in Figure below. Using t_A

= 0 as the time the stone leaves the thrower’s hand at position , determine

(a) the time at which the stone reaches its maximum height,

(b) the maximum height,

(c) the time at which the stone returns to the height from which it was thrown,

(d) the velocity of the stone at this instant, and (e) the velocity and position

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Emily menantang David temannya untuk menangkap sebuah uang dolar sebagai berikut. Dia memegang uang secara vertikal, seperti pada gambar, dengan titik tengah uang kertas tersebut berada