TOPIC 3: DYNAMICS Flashcards
[Definition] Newton’s Third Law of Motion
When body A exerts a force on body B, body B exerts on body A a force of the same type, equal in magnitude and opposite in direction.
[Definition] Newton’s First Law of Motion
An object stays at rest or continues to move at constant velocity unless a resultant force acts on it.
[Definition] Weight
Weight of the body is the force acting on the body due to a gravitational field.
[Definition] Linear Momentum - N1L
Linear momentum of a body is the product of its mass and its velocity
[Formula] Linear Momentum
p = mv
Unit of linear momentum
kgms⁻¹ or Ns
[Definition] Newton’s Second Law of Motion
The rate of change of momentum of a body is directly proportional to the resultant force acting on it and takes place in the direction of the resultant force
[Formula] N2L
Fnet = dp/dt
Fnet = Δ(mv) / Δt
Fnet = ma
What does the weighing scale measure?
It measures the normal contact force exterted on us when we are on it
What is ‘weightlessness’?
It refers to the state where a body experiences no contact force(s)
True weight VS apparent weight
True weight does not change as long as the gravitational field is constant and uniform
Apparent weight is given by the reading on a weighing scale, which changes with the normal contact force between our bodies and the weighing scale
[Definition] Impulse
The product of the force and time duration of impact
[Formula] Impulse
Δp = (Fnet)(Δt)
Δp = mΔv
[Definition] Principle of Conservation of Linear Momentum
The total linear momentum of an isolated system of interacting bodies before and after collision remains constant if no net external force acts on the system.
*Total momentum constant but individual momentum changes
[Definition] Elastic Collision
Total kinetic energy of system of bodies before and after collision remains the same
