By Prof. Liwayway Memije-CruzAll About Forces

Force any influence capable of producing a

change in the motion of an object. is a push or pull acting upon an object as a

result of its interaction with another object. Whenever there is an interaction between

two objects, there is a force upon each of the objects.

When the interaction ceases, the two objects no longer experience the force. Forces only exist as a result of an interaction.

Units of Force

Classification of Forces

Based on Line of Action

forces that all go through one point of intersection.

concurrent forces can be added together to obtain the resultant. If the forces are in equilibrium, the resultant will be zero.

Concurrent Forces

Concurrent Forces: Tug of War If two people stand the ends of a rope and pull on

it, the forces are concurrent because the effect of the forces will intersect at the same point.

Non – concurrent Forces are two or more

forces whose magnitudes are equal but act in opposite directions with a common line of action.

Non-concurrent Forces: Cycling When a cyclist

pedals, his or her feet are parallel. One foot pushes a petal forward while the other pushes the other pedal backward. These twoforces cause the wheels on the bike to rotate.

Coplanar Forces A set of points,

lines, line segments rays or any other geometrical shapes that lie on the same plane

Exercise Which of the

following statements are correct?

1. Points F, A, L, C, G, E, O and B are coplanar.

2. Points G, E, F and A are coplanar.

3. O, A and B are coplanar.4. Points F, A, L, I, C are

coplanar

Answer

A. 1 and 2 only

B. 3 and 4 only

C. 4 onlyD. 1 only

1. a plane is a flat surface that extend in all directions,

2. F, A, L, I, C lie on plane F, while G, E, O lie on plane G so the first statement is false. A plane can be named either by a single capital letter or by naming at least three non-collinear points in the plane.

3. Points G, E and F, A lie on two separate planes, so statement 2 is false.

4. O and A lie on different planes…Third is false

5. F, A, L, I, C lie on the same plane. Fourth is True.

Solution

Non-coplanar points which do not lie in the same

plane or geometrical plane. 

Based on the Effects of Forces

two forces acting in opposite directions on an object, and equal in size.

Anytime there is a balanced force on an abject, the object stays still or continues moving continues to move at the same speed and in the same direction.

Balanced forces can be demonstrated in Hanging, Floating and Standing/sitting objects.

Balanced Forces

Examples of Balanced Forces

Newton’s First Law of Motion An object at rest

stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

Unbalanced Forces when two forces acting

on an object are not equal in size.

causes can cause: a still object to movea moving object to speed up or slow downa moving object to stopa moving object to change direction

Based on the intersection of bodies.

a force that acts at the point of contact between two objects, in contrast to body forces.

Contact Forces

the force of a gravitational field

the force of a magnetic field

the force of an electric field

Non-contact forces

Non-contact Forces

References: http://eschooltoday.com/science/forces/

unbalanced-forces.html http://www.physicsclassroom.com/

Class/newtlaws/U2l1d.cfm https://prezi.com/rybrk-acfh7h/types-of-

contact-and-non-contact-forces/ https://www.reference.com/science/

concurrent-forces-physics-755bd4f9da9b8c9a