Physical sciences(p1) G.12
Newton’s Laws
Made easy with Nathi.
Newton’s laws: A group of principles in physics to describe the relationship between the
motion of an object relative to its environment.
NEWTON’S 1ST LAW OF MOTION
Definitions:
Vector} A physical quantity that has both magnitude and direction
Scalar} A physical quantity that has only magnitude
Newton’s 1st law =An object will continue moving at a constant velocity or remain at rest
unless a non-zero(resultant) force acts on it.
INERTIA=The opposition of any change in the original state of motion.
Newton’s 2nd law of motion=When a non-zero force acts on an object, the object will
accelerate at an acceleration directly proportional to the force and inversely proportional to
the mass of the object.
Newton’s 3rd law=When object A exerts a force on object B, object B will simultaneously
exert a force of equal magnitude in an opposite direction.
The forces experienced cannot cancel out each other because they act on different
bodies.
SI units
Force=N (vector quantity)
Velocity=m.s^(-2) [vector quantity]
Speed= m.s^(-1)[scalar quantity]
NEED TO KNOW
• A force is always exerted BY something ON something else.
• Distinguish between forces acting ON the body and forces exerted BY the body. Only the
forces acting ON the body affects its motion.
• “Gravity” is not a force, it should be “gravitational force of earth ON the body”.
FORCES
Newton’s Laws
Made easy with Nathi.
Newton’s laws: A group of principles in physics to describe the relationship between the
motion of an object relative to its environment.
NEWTON’S 1ST LAW OF MOTION
Definitions:
Vector} A physical quantity that has both magnitude and direction
Scalar} A physical quantity that has only magnitude
Newton’s 1st law =An object will continue moving at a constant velocity or remain at rest
unless a non-zero(resultant) force acts on it.
INERTIA=The opposition of any change in the original state of motion.
Newton’s 2nd law of motion=When a non-zero force acts on an object, the object will
accelerate at an acceleration directly proportional to the force and inversely proportional to
the mass of the object.
Newton’s 3rd law=When object A exerts a force on object B, object B will simultaneously
exert a force of equal magnitude in an opposite direction.
The forces experienced cannot cancel out each other because they act on different
bodies.
SI units
Force=N (vector quantity)
Velocity=m.s^(-2) [vector quantity]
Speed= m.s^(-1)[scalar quantity]
NEED TO KNOW
• A force is always exerted BY something ON something else.
• Distinguish between forces acting ON the body and forces exerted BY the body. Only the
forces acting ON the body affects its motion.
• “Gravity” is not a force, it should be “gravitational force of earth ON the body”.
FORCES
