1. Definition of Force
• Force: A push or pull acting on an object that can change its
state of motion or shape.
• Formula:
F=maF = ma
Where:
o FF = Force (Newton, NN),
o mm = Mass (kg),
o aa = Acceleration (m/s²).
• Vector Quantity: Force has both magnitude and direction.
2. Effects of Force
1. Changes the state of motion of a body.
2. Can cause a body to accelerate or decelerate.
3. Can change the direction of motion.
4. Can change the shape or size of a body (e.g., compressing a
spring).
3. Types of Forces
Contact Forces:
• Acts only when two objects are in physical contact.
1. Frictional Force:
o Opposes the motion of objects.
o Depends on the nature of surfaces and normal reaction.
, o Formula: f=μNf = \mu N Where μ\mu is the coefficient of
friction, and NN is the normal force.
2. Normal Reaction:
o Perpendicular force exerted by a surface to support an
object resting on it.
3. Tension:
o Force transmitted through a string, rope, or cable when it
is pulled tight.
Non-Contact Forces:
• Act without physical contact.
1. Gravitational Force:
o Attractive force between two masses.
o Formula: F=Gm1m2r2F = G \frac{m_1 m_2}{r^2} Where:
▪ GG = Gravitational constant
(6.67×10−11 Nm2/kg26.67 \times 10^{-11} \,
\text{Nm}^2/\text{kg}^2),
▪ m1,m2m_1, m_2 = Masses,
▪ rr = Distance between centers of the masses.
2. Electrostatic Force:
o Force between charged particles.
o Formula: F=kq1q2r2F = k \frac{q_1 q_2}{r^2} Where kk is
Coulomb’s constant.
3. Magnetic Force:
o Force due to magnetic fields.
4. Newton’s Laws of Motion
First Law (Law of Inertia):