Tugas Mata Kuliah Konsep Dasar IPA

1. Dynamics Of The
Particles
Group 2 :
ULFA SAFITRI 16010644041
LAILATUL MUFARROHAH 16010644073
BAITI NUR ROISAH 16010644102

2. What is the Dynamics of the
particles?
Particle dynamics is the science that discusses the forces
that cause a particle that initially remains motionless, or that
accelerates or retards the motion of a particle.

3. What can makes object move?
• Aristoteles (384-322 SM) :
force, pull or thrust is required to keep things moving.
• Galileo Galilei (1600) :
moving objects have a "quantity of motion" intrinsically.
• Issac Newton (1665-1666) :
Newton's law contains three concepts: mass, force, momentum

4. Newton’s First Law
The Law Of Inertia
An object at rest remains at rest, or
if in motion, remains in motion at a
constant velocity unless acted on by
a net external force.

5. Example :
• A soccer ball does not stop in the air
• A pencil does not roll except on rolling

6. NEWTON’S SECOND LAW
F is the unbalanced force
m is the object's mass
a is the acceleration that the force causes
∑F = m a

7. EXAMPLE
• If an unbalanced force of 600 newtons acts on a body to
accelerate it at +15 m/s2, what is the mass of the body?
• F = ma
m=F/a
m = 600n/15 m/s2
m= 40 kg

8. NEWTON’S THREE LAW
For every action there is an equal and opposite re-action.
• Expectation in everyday life 1. When you hit the table then the
table will give the force back on your hand with the same big
and opposite direction with the direction of style you give.
Therefore the more you hit the table the more pain your
hands will become

9. Usage of Newton's Law
Force includes vector. Summing force = vector sum.
FX = the number of force components on the x axis
FY = the number of force components on the y axis
FR = resultant force
FR = √F12 + F22 + 2F1F2 cos a
FR = √FX2 + FY2

10. Regular Straight Motion (GLB)
Regular Straight Motion (GLB) is a straight motion in the
horizontal direction with a fixed velocity .
D (difference) --> the average value
d (differential) --> the momentary value
S = X = v. t
a = Dv / Dt = dv / dt = 0
v = Ds / Dt = ds / dt = fixed

11. Example
A particle moves along the x-axis with its path equation: X = 5t2 + 1 with X in meters and t
in seconds. Specify:
a. Average velocity between t = 2 seconds and t = 3 seconds
b. Speed ​​at t = 2 seconds
c. Distance traveled in 10 seconds
d. The average acceleration between t = 2 seconds and t = 3 seconds
Answer :
a. v average = DX/Dt
= (X3 – X2) / (t3 – t2)
= [(5.32 + 1) – (5.22 + 1) / (3-2)]
= 46 – 21 = 25 m/s
b. v2 = dx/dt (X = 5t2 + 1) = 10.t = 10.2 = 20 m/s
c. X10 = (5.102 + 1) = 501 m ; X0 = 1 m
Distance traveled in 10 seconds = X10 – X1 = 501-1 = 500 m
d. a mean= Dv/Dt
= (v3 – v2)/(t3-t2)
= (10.3-10.2)/(3-2)
= 10 m/s2

12. Straightforwardly Changed Motion
(GLBB)
is a straight motion in the horizontal direction with velocity (v)
that changes at any time due to fixed acceleration (a).
vt = instantaneous velocity of the object
v0 = first velocity of the object
S = spacing/distance traveled by object
vt = v0 ± a.t
vt2 = v02 ± 2 a S
S = v0 t + ½ a t2

13. Example
Distance PQ = 144 m. Object B moves from point Q to P with an
acceleration of 2 m / s2 and an initial velocity of 10 m / s. It moves 2
seconds later from point P to Q with acceleration of 6 m / s2 without
initial velocity. Things A and B will meet at what distance?
Answer:
Since object A moves 2 seconds later after object B then maka tB =tA +
2
SA = v0.tA + ½ a.tA
2 = 0 + 3tA
2
SB = v0.tB + ½ a.tB
2 = 10(tA + 2) + (tA + 2)2
Suppose the two objects meet at point R then
SA + SB = PQ = 144 m
3tA
2 + 10(tA + 2) + (tA + 2)2 = 144
4tA
2 + 14tA – 120 = 0
2tA
2 + 7tA- 60 = 0
So the two objects will meet at a distance SA = 3tA
2 = 48 m (from point
P)

14. Free Falling Motion
It is the motion of falling objects in the vertical direction of
a certain height at the first velocity.
g = earth's gravitational acceleration
y = h = the height of object takes in the vertical direction
t = the time it takes for the object to take the path
y = h = 1/2gt2
v = g t
v2 = 2gh

15. Example
An object dropped from a plane that was traveling horizontally
720 km / h from a height of 490 meters. Calculate the
distance of the object fall in the horizontal direction! (g = 9.8
m / s2).
Answer:
vx = 720 km/hours = 200 m/s
h = 1/2 gt2
490 = 1/2.9,8 . t2
t = 10 detik
X = vx . t = 200. 10 = 2000 meters

16. Upward Vertical Movement
It is the motion of an object thrown with a first velocity in the vertical
direction,
vt = speed after t seconds
v0 = initial velocity of the object
g = earth's gravitational acceleration
h = altitude or object movement
t = the time it takes for the object to take the path
vt = vo – gt
vt2 = v0
2 – 2gh
h = vot – 1/2 gt2

17. Example
a ball thrown to the op with the speed of 10m/s, 1 second later the second
ball was hit by a vertical to come up with the speed of 25 m/s. the reached
height the second ball when he met with the first ball is..... (g= 10 m/s2)
answer:
hA = hB
ball A --> v0A = 10 m/s
ball B --> v0B = 25 m/s , t = t-1
v0A t - 1/2 gt2 = v0B t- 1/2 gt2
10t - 5t2 = 25(t-1) - 5(t-1)2
10t - 5t2 = 25t- 25 - 5t2 + 10t - 5
25t = 30
t = 6/5
hA = v0A t - 1/2 gt2
= 10. 6/5 - 1/2 . 10. (6/5)2
= 4,8 m
hA = hB

18. Friction
• is a force that occurs
between two surfaces
that moving relatively
opposite.
• The friction force that
occurs during a
stationary object is called
static frictional force.
fs ≤ μs N
μs = static frictional
coefficient

19. when F4 is magnified only slightly, the object will move
the friction force that occurs during a moving object is called a
kinetic frictional force.
fk = μk N
μk = kinetic friction coefficient

20. Dynamic Circular Motion
A particle that moves in a circle at a constant velocity, the
particle is accelerated (centripetally) of:
in the direction toward the center of the circle, in which it acts
centripetal force.
The reaction of the centripetal force is the centrifugal force,
which is of equal magnitude but opposite direction to the
centripetal force.
a = v2/r

21. Half Parabolic Motion
The object thrown horizontally from a certain height.
a. Motion in the direction of X axis (GLB)
b. Motion in the direction of Y axis (GJB / GLBB)
vx = v0
Sx = X = vx t
vy = 0
y = ½ gt2

22. Example
From the top of the building with height 125 m, the ball was kicked
across to the speed of 10 m/s. specify :
a. the time required the ball to reach land?
b. the distance across which the ball?
answer:
v = 10 m/s
h = 125 m
a. h = 1/2 gt2
125 = 1/2 . 10 t2
125 = 5 t2
t = 5 s
b. x max = v t
= 10 . 5 = 50 m

23. Parabolic / Bullet Motion
Objects thrown up with a certain angle.
a. The direction of sb-X (GLB)
b. The Directions of sb-Y (GLBB)
v0x = v0 cosq (fixed)
X = v0x t = v0x cosq t
v0y = v0 sinq
Y = v0yt – 1/2 gt2 = v0y.sinq.t – 1/2 gt2
vy = v0 sinq – gt
top = v0sinq/g
h max = v0
2 sin2q/2g
vt = √(vx)2 + (vy)2

24. Example
Bullet A and bullet B fired from the same gun with different angle of
elevation; A bullet with 30o and bullet B with an angle of 60o. What
is the maximum height ratio of bullet A and bullet B?
Answer:
Bullet A:
hA = v0
2sin230o / 2g
= v0
2 1/4 / 2g
= v0
2 / 8g
Bullet B:
hB = v0
2sin260o / 2g
= v0
23/4/ 2g
= 3v0
2 / 8g
hA : hB = v0
2 / 8g : 3v0
2 / 8g = 1 : 3

25. FORCE
• The definition of force in the acceleration that occurs by a
standard object when available in a particular environment
accordingly.
• Force is a vector, there is a large, there is a direction and
direction of seeing each other parallelogram.
• If several forces act on an object, each of which is self-
accelerated separately, the acceleration is the number of
vectors of the separate accelerations.

26. System of Mechanics Unit
• Styles are defined as forces that give rise to one-unit
acceleration when done on one-unit mass.
• In SI, the force unit is a force that accelerates the 1kg mass by
1 m / 𝑠 ^ 2 and this unit is called Newton.
• In cgs units, force units are forces that accelerate a one-g mass
by 1 cm / 𝑠 ^ 2, this unit can be called dyne.
In a unit system of BE, selected as the fundamental quantities
are force, length, and time, while mass as a derived quantity.
• In systems that use mass, length, and time as the fundamental
quantities, the dimension of force is mass x length / time ^ 2.
Or 〖𝑀𝐿𝑇〗 ^ 2.

27. Force Statistics for Measuring
Force
• The force is defined by measuring the acceleration generated
on a standard object drawn by an outstretched spring.
• This static method force uses the fact that if an object,
subjected to some force does not accelerate, the sum of
vectors of all forces acting on it must be zero.
• Springs that work on the springs are always the same if the
pointer scales the same place pointer. The screened balance
can be used to measure other unknown forces.

28. Mass and Weight
• The mass is what the porcelain has on the table when you put
the tablecloth out from under it.
• Weight is a force that acts on an object a tug by the earth or
other large object.
• The weight of an object is a force, a vector quantity, and we can
write the above equation as a vector equation:
w = mg
Remember that g is the magnitude of g, the acceleration of
gravity, so g is always positive by definition thus w as in the
above equation is the weight and always positive

29. Conclusion
• A force is one that can change the condition of the motion of an object,
can change the shape of the object.
• Law I Newton
An object will be stationary or move perpendicularly if the entire force
acting on an object is zero.
ΣF = 0
• Newton's Law II
If the magnitude of force acting on non-zero objects, then the object
will experience an acceleration of magnitude:
a = (Σ𝐹) / (Σ𝑚)
• The weight of an object is the mass of the object that is affected by the
acceleration of earth's gravity:
W = mg
• The action-reaction force is a pair of two forces of equal magnitude,
opposite direction and is the result of the interaction of two objects.