What is Force?
Definition: Force is the effect that
changes (or tries to change) the motion state of an object or the
object's shape.
Vector Quantity: Just like velocity and
acceleration, Force is a vector quantity (it has both magnitude and
direction).
Effects: The behavior of an object
depends on the resultant forces. For example, when you kick a
football, you control its speed and direction.
Mechanical Types: Forces can manifest in
various ways , including:
Push and Pull
Tensile force and
Compression force
Rotation force and Torsion
force
Unit of Measurement: The international unit for
Force is the Newton (N).
1 N = 1kg.m/s2
2. Classifying Forces
We can
categorize forces into two main groups based on how they interact:
A. Contact Forces:
These occur when two
objects have direct contact.
Measurement: We can measure force using
a spring scale.
B. Base-Forces (Forces in Nature):
These forces exist in
nature without direct contact between objects (action at a
distance). Physicists identify three main kinds in this chapter:
3. The "Base-Forces" in Detail
a. The Gravity Force:
This is a reciprocal
attraction between any two masses in the universe.
Example: The Sun keeps the Earth
rotating in its orbit.
Weight: This is defined as the
attraction force that a planet or moon imparts to objects near its
surface.
b. The Electric and Magnetic
Forces:
Electric: The force between electrical
charges. Example: A comb rubbed with wool attracting paper pieces.
Magnetic: The force between two
magnetic poles or a magnet attracting an iron piece.
c. Nuclear Force:
These exist inside the
nucleus of an atom and have two types:
1. Strong
Nuclear Force: Connects
the nucleons (protons/neutrons) with each other.
2. Weak
Nuclear Force:
Responsible for the decay of beta particles inside the nucleus.
Q1: How
does the textbook define "Force"?
Answer: Force is defined as the effect
that changes or tries to change the motion state of the object or the object's
shape.
Q2: Is
Force a scalar or vector quantity? What is its unit?
o Answer: It is a vector quantity
(has direction). Its unit is the Newton, which equals 1 N = 1kg.m/s2.
Q3: What
is the difference between "Contact Forces" and
"Base-Forces"?
Answer: Contact forces require objects
to touch (have direct contact). Base-forces are known in nature where there is no
direct contact between the objects (like gravity or magnetism).
Q4:
According to the text, what is the specific function of the "Weak Nuclear
Force"?
Answer: The weak nuclear force is
responsible for the decay of beta particles that happens inside the
nucleus.
Q55: What
is "Weight" defined as in the section on Gravity?
Answer: Weight is the attraction force
that a planet or the moon imparts to near objects.
