Transcript Motion

Motion
Cristinebi F. Abanador
Jana Marie P. Mancenido
ABMCJ-2A
What is MOTION?
• a change in position of an object with respect
to time.
• typically described in terms
of velocity, acceleration,
displacement and time.
• observed by attaching a frame of reference to
a body and measuring its change in position
relative to another reference frame.
Scalars and Vectors
• Physics is a mathematical science.
• The motion of objects can be described by
words.
• Scalars are quantities that are fully described
by a magnitude (or numerical value) alone.
• Vectors are quantities that are fully described
by both a magnitude and a direction.
Check Your Understanding
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a. 5 m
b. 30 m/sec, East
c. 5 mi., North
d. 20 degrees Celsius
e. 256 bytes
f. 4000 Calories
Types of motion
1.) Simple harmonic motion
• a type of periodic motion where the
restoring force is directly proportional to
the displacement.
• Ex. motion of a simple
pendulum & molecular vibration
• A simple harmonic oscillator is attached
to the spring, and the other end of the
spring is connected to a rigid support
such as a wall. If the system is left at rest
at the equilibrium position then there is
no net force acting on the mass.
However, if the mass is displaced from
the equilibrium position,a
restoring elastic force which obeys
Hooke's law is exerted by the spring.
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• Mathematically, the restoring force F is
given by
where F is the restoring elastic force
exerted by the spring (in SI units: N), k is
the spring constant (N·m−1), and x is
the displacement from the equilibrium
position (in m).
Mass on a spring
• A mass m attached to a spring of spring
constant k exhibits simple harmonic
motion in space. The equation
shows that the period of oscillation is
independent of both the amplitude and
gravitational acceleration
Mass on a simple pendulum
2.) Linear motion
• motion along a straight line, and can
therefore be described mathematically using
only one spatial dimension.
An example of linear motion is that of a
ball thrown straight up and falling back
straight down.
Displacement
• Since linear motion is a motion in a single
dimension, the distance traveled by an object
in particular direction is the same as
displacement. The SI unit of displacement is
the metre.
• Δx = x2 − x1
=Final-initial
3.) Reciprocating motion
• a repetitive up-and-down or backand-forth motion.
• found in a wide range of mechanisms,
including reciprocating
engines and pumps.
i.e. vibration
Double-acting stationary
steam engine demonstrating
conversion of reciprocating
motion to rotary motion.
The piston is on the left,
the crank is mounted on the
flywheel axle on the right.
Machine
demonstrating
conversion of rotary
motion to
reciprocating motion
using gears. The
bottom pair of gears
drives the mechanism.
4.) Brownian motion
• botanist Robert Brown
• random drifting of particles suspended in a
fluid (a liquid or a gas) or the mathematical
model used to describe such random
movements, which is often called a particle
theory.
i.e. the random movement of particles
5.) Circular motion
• a movement of an object along
the circumference of a circle or rotation along
a circular path or a circular orbit.
Ex.
• an artificial satellite orbiting the Earth at
constant height;
• a stone which is tied to a rope and is being
swung in circles;
• a car turning through a curve in a race track;
• an electron moving perpendicular to a
uniform magnetic field;
• and a gear turning inside a mechanism
6.) Rotational motion
• Rotation around a fixed axis
e.g. Ferris wheel
Examples and applications
●Constant angular speed
-simplest case of rotation around a fixed axis
●Centripetal force
-a force which keeps a body moving with a
uniform speed along a circular path and is
directed along the radius towards the centre.
7.) Curvilinear motion
• Example: A stone thrown into the air in
an angle.
8.) Rolling
• combines rotation (commonly, of an axially
symmetric object) and translation of that
object with respect to a surface (either one or
the other moves), such that, if ideal conditions
exist, the two are in contact with each other
without sliding. This is achieved by a
rotational speed at the line or point of contact
which is equal to the translational speed.
e.g. the wheel of a bicycle
A VERY EASY QUIZ 
1. These are quantities that are fully described by both a
magnitude and a direction.
2. The example of this type of motion is vibration.
3. This is a type of periodic motion where the restoring force
is directly proportional to the displacement.
4. A car going down the road has a speed of 50 mph. Its
velocity is 50 mph in the northeast direction. What kind of
quantity of motion is this?
5. It is typically described in terms of velocity, acceleration,
displacement and time.
6. It is a motion along a straight line, and can therefore be
described mathematically using only one spatial dimension
7. A repetitive up-and-down or back-and-forth motion.
8. Give an example of curvilinear motion.
9. It is a movement of an object along the circumference of
a circle or rotation along a circular path or a circular orbit.
10. Give an example of rotational motion.
answers
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1. vector
2. reciprocating motion
3. simple harmonic motion
4. vector
5.motion
6. linear motion
7. reciprocating motion
8. A stone/ball thrown into the air in an angle.
9. circular motion
10. ferris wheel