Nature of Forces

Force is needed to stop an object.

Force always results to motion.

Force can act even at a distance.

Agree or Disagree

Objects have the tendency to remain at rest.

Objects have the tendency to resist change.

S C W P F I R J A I

V S I C C B W E I Y

N O I T C I R F T G

N O T W E N G I R A

J V Z E L N V Z E L

F R P X N A G H N I

V C Y W R S M A I L

G V Z G B X I R M E

C O N T A C T O O O

O G Z X M N B J N N

Word Search

What is the effect of understanding the nature of force?

Tension – Contact – Newton – Galileo – Friction –

Gravity – Normal – Magnetic – Inertia -

vector quantity (magnitude and direction)

Measured in Newton (N)1 N of force is required to give a 1-kg mass an acceleration of 1 m/s2.

1 N = 1 kg m/s2

Force

1. Force can make an object move starting from a rest position.

2. Force can make a moving object stop.

3. Force can change the direction of a moving object.

What changes can force do to motion?

Have you ever felt that that you are connected to someone or something even if there is physical separation?

What makes you connected?

Contact Forces – forces that require physical contact between objects

Non-Contact Forces – also known as action-at-a-distance forces or field forces

- it does not require physical contact to have any effect on the other object.

Applied force – a force which is applied to an object by another object or by a person. The direction of the applied force depends on how the force is applied.

Normal Force (N)– referred to as pressing force and is always directed towards the object and acts perpendicularly.

Types of Contact Forces

Frictional force (f) – opposes the motion of the object

- results when two surfaces are pressed together closely, causing attractive intermolecular forces between the molecules of the two different surfaces.- acts parallel to the surface.- f=µN (µ=coefficient of friction, N=Normal force)

Air Resistance Force – a special type of frictional force

- frequently be ignored due to its negligible magnitude.- most noticeable in objects which travel at high speed or in objects with large surface areas.

Tensional force (T) – a force transmitted through a string, rope, or wire when pulled tight by force acting at each end.

- the direction is always away from the object.

Spring force – the force exerted by a spring upon any object which is attached to it.

- acts to restore the object, which compresses or stretches a spring, to its ret or equilibrium position.

Force of Gravity (Weight) – the force with which the Earth, moon, or other massive body attracts an object towards itself.

- the weight of the object- W=mg (g=9.8 m/s2, m=object’s mass (kg))

Types of Non-Contact Forces

Electrical force – force that exists between charges (attractive or repulsive).

Magnetic force – exists in magnets (attract or repel)

Balanced Forces – are equal forces acting in opposite directions; thus, they have zero net force.

Unbalanced Force – has a nonzero net force; thus it produces acceleration.

If you are to exert force on something, is it important to get familiar with the other forces involved?

How does the knowledge of the other forces help you in doing a particular task?

How can you show propriety and cautiousness in dealing with the different forces?

How can you relate love to contact and non-contact forces?

A. Study for a written learning assessment on Wednesday, June 18.Topics:1. Contact and non-contact forces and their types.2. Balanced and unbalanced forces.

Assignment

B. Bring the following materials on each date:

June 17, Wednesday- 3 Balls of

various sizes

- Glass- Coins- sheet of

paper- straw

(Zagu)

June 18, Thursday- metal ball

of the shot put or any two balls of different masses

- toy cart- string

June 22, Monday- Balloon- 3 meter

length of nylon string

- plastic straw

- scotch tape