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 a. 5 m b. 30 m/sec, East c. 5 mi., North d. 20 degrees Celsius e. 256 bytes f 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. >>>>

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 = x 2 − x 1 =Final-initial

3.) Reciprocating motion a repetitive up-and-down or back-and- 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

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