Physics Unit: Force & Motion What is physical science?

A. Physical science is a field of science that studies matter and energy. B. Physical science has 2 main branches:

1. PHYSICS: the study of how matter and energy interact •  robotics, nuclear energy, solar

panels 2. CHEMISTRY: the study of the

structure, makeup, and changes of matter •  chemicals, acids & bases,

medicines

What is energy? A.  ENERGY: the ability to do work or

make something happen B.  All forms of energy fall under two

categories: 1.  POTENTIAL ENERGY: stored

energy that could make something happen a.  Chemical Energy b.  Nuclear Energy c.  Stored Mechanical Energy d.  Gravitational Energy

2.  KINETIC ENERGY: used energy that is making something happen a.  Radiant Energy b.  Thermal Energy c.  Motion d.  Electrical Energy e.  Sound

What are the different forms of energy?

A.  There are many different forms of energy to make things happen.

B.  Below are 6 of the major forms: 1.  MECHANICAL ENERGY: the

energy in moving objects 2.  ELECTRICAL ENERGY: energy

from the flow of electrons 3.  ELECTROMAGNETIC ENERGY:

energy in the form electrical and magnetic waves that can travel through space

4.  HEAT ENERGY: thermal energy that comes from moving particles of matter (friction)

5.  CHEMICAL ENERGY: energy that holds particles of matter together (chemical bonds)

6.  NUCLEAR ENERGY: energy stored in an atom’s nucleus

What is a wave? A.  WAVE: a disturbance that transports

energy from one place to another. 1.  A wave is energy that travels over a

distance. 2.  There are two major forms of waves:

a.  MECHANICAL WAVES: waves that travel through matter like air or water

b.  ELECTROMAGNETIC WAVES: waves that can travel through matter or empty space

What is a wave? B.  Waves that travel through matter can do it one of two ways:

1.  TRANSVERSE WAVE: waves that move up and down a.  There are two parts to a transverse wave

i.  CREST: the highest point of a wave ii.  TROUGH: the lowest point of a wave

2.  LONGITUDINAL WAVE: waves that move back and forth a.  There are two parts to a longitudinal wave

i.  COMPRESSION: where the particles are close together ii.  RAREFACTION: where particles are far apart

What is mechanical energy? A.  MECHANICAL ENERGY: the

energy an object has that causes it to move

B.  Mechanical energy can come in one of two ways: 1.  STORED MECHANICAL ENERGY:

potential mechanical energy that could cause an object to move

2.  MOTION: kinetic mechanical energy that causes an object to move

C. A force acting on an object is required for mechanical energy

What is a Force? A.  FORCE: a push or pull exerted on an object B.  To describe a force, you must know a force’s size and

direction C.  Size and direction can cause one of two situations:

1.  BALANCED FORCES: forces on an object equal in size but opposite in direction

2.  UNBALANCED FORCES: forces on an object that are no longer balanced, causing a change in the motion of an object

What is a Force? D.  Forces are drawn as arrows of different sizes.

1.  Arrows show direction 2.  Different sizes show how strong the force is

E.  Forces are measured using instruments: 1. A spring scale is used to measure a force using Newtons 2. NEWTON: a standard unit of force depicted as an N

3 N 3 N 10 N 1 N

8 N

3 N

Which major forces affect the motion of objects? A. Gravity is one of the major forces

acting on objects 1.  GRAVITY: a force of attraction

between all objects in the universe

B.  On Earth, objects are pulled to the center of the planet by the dense mass of the planet’s core

C.  Friction is another major force moving objects must contend with: 1.  FRICTION: a force that pushes

back on a moving object 2.  This force often occurs when an

object rubs against, moves over or through another type of matter

3.  Friction can cause heat as a result of rubbing

What is Magnetism? A.  MAGNETISM: the force (push or pull)

produced by magnetic materials B.  MAGNET: a material that pulls or

attracts the metals iron, cobalt, and nickel 1.  All magnets have two common

properties: a.  MAGNETIC POLES: two

places on a magnet where the forces are the strongest i.  The two poles are marked

North (N) and South (S) ii.  Opposite poles are attracted to

each other iii.  Similar Poles repel each other

b.  MAGNETIC FIELD: the space around a magnet where the force acts on other objects

What is Magnetism? C. Permanent magnets can cause iron, cobalt, or nickel to

become temporary magnets. 1.  Each atom in an object as positive and negative end 2.  When metals are pulled on by a magnetic field, these ends

line up, with positive being attracted to negative. 3.  This lining up creates a magnetic field around the metal

How is motion described? A.  Motion can be described in terms of speed and

direction: 1.  VELOCITY: the speed and direction of a moving

object a.  Two things must be measured to determine

speed i.  Distance in meters (m) ii.  Time in seconds (s)

b.  Direction must be figured out using a compass to determine north, south, east or west.

c.  Velocity can be written as a formula: i.  Distance ÷ Time = Speed & Direction ii.  m ÷ s = m/s & Direction

What is Work? A.  WORK: force exerted on an object that moves it over

a measurable distance 1.  Two things must be measured to determine work:

a.  Force in newtons (N) b.  Distance in meters (m)

2.  If an object does not move, no work is accomplished.

B. Work can be written as an formula: 1.  Force x Distance = Work 2.  N x m = J 3.  Work is written in Joules (J)

a. JOULE: a unit of work equal to a force of 1 N that moves an object 1 m.

What is a Simple Machine?

A.  MACHINE: a device that makes work easier 1.  A machine can make work easier in three ways:

a.  Reducing the size of the effort force b.  Changing the direction of the effort force c.  Changing the speed at which work is done

2.  Most machines are a combination of two or more simple machines: a.  Wheel and Axle b.  Lever c.  Inclined Plane

How do Levers Work? A.  LEVER: a bar or plane that is free to pivot or turn around a fixed

point 1.  Two major parts of a lever:

a.  FULCRUM: the fixed point a lever pivots or turns around b.  ARM: the bar or plane pivoting over the fulcrum

B.  A lever does two things to make work easier: 1.  Reduce the size of the force 2.  Changes the direction of the force

How do Wheels & Axles Work? A.  WHEEL & AXLE: a circular object that turns around a fix point

or rod 1.  It reduces the friction between weight and the surface it moves

over. 2.  The longer the diameter the further the distance the wheel will

move.

How do Wheels and Axles Work? B. Wheel & axles are parts of other simple machines:

1.  Pulleys are a wheel and axle with a rope wrapped around it 2.  Gears are special wheels with teeth able to bite and turn each

other.

How Do Inclined Planes Work? A.  INCLINED PLANES: a slanted surface or ramp

1.  An inclined plane makes work easier by changing the angle you have to exert a force to lift an object.

2.  The lesser the angle of an inclined plane, less force needs to be exerted.

How Do Inclined Planes Work? B. Inclined planes are parts of other simple machines:

1.  A wedge is two planes back to back 2.  A screw is an inclined plane wrapped around a cylinder.