FISIKA DASAR

FISIKA DASARBy: Mohammad Faizun, S.T., M.Eng.

Head of Manufacture System LaboratoryMechanical Engineering Department

Universitas Islam Indonesia

MOTION (Gerak)?

Gerak adalah proses berpindahnya suatu objek. Berpindah berarti posisi relatifnya berubah.

Dari gambar di atas, sebutkan benda-benda mana saja yang bergerak! Jelaskan!

Kinds of motion:

1.according to the path of objectsa.linear motion (translational motion)b.circular motionc.elliptic motiond.projectile motion

2. according to the speed of objectse.uniform motion

the object moves in constant speedf. non uniform motion: speeding up and slowing down.

Straight motion

Projectile motion

Straight motion

Circular motion

elliptical motion

LINEAR UNIFORM MOTIONDIMENSION 1 (Straight Line)

A. Motion in straight path with constant velocity

tsv

= velocity (m/s)displacement (m)

Δt = time span (s)

vs

01 sss

Make the position vs time graph if the constant velocity is 20 m/s!

• Negative direction

Make the position vs time graph if the constant velocity is -20 m/s!

• EXERCISE (PR disubmit senen 26 September 2011)

(Motion in straight path with constant velocity)

1. A car moves forward in straight path 100 meters long. The speed is 10 m/s. Find the time needed by the car!

2. A bus moves in straight way with velocity 120 km/h. Please convert the speed into m/s!

3. The motorcycle goes form A at 07.00 with speed 90 km/h, the ambulance goes from B at 7.30 with speed 100 km/h. Determine the place where they meet and what is the time?

A B240 km

4. Sebuah benda mungkin bergerak dengan grafik seperti di bawah. Tentukan:

a. kecepatan benda tersebut!b. Posisi benda tersebut pada 20 detik pertama!c. tentukan jarak yang ditempuh selama 20 detik!

10

t (s)

50

s (m)

10

-25

t (s)

s (m)

A B

5. Sebuah benda mungkin bergerak dengan grafik seperti di bawah. Tentukan:

a. kecepatan benda tersebut!b. Posisi benda tersebut pada 20 detik pertama!c. tentukan jarak yang ditempuh selama 20 detik!

10

t (s)

50

s (m)

A B

t (s)

50

s (m)

B. Motion in straight path with constant acceleration

tsv

= acceleration (m/s2)a

tva