chap 4: dyanmics 🚅 Flashcards
define mass
property of a body which resists change in motion
define momentum
product of its mass and its velocity
state Newton’s First Law
in the absence of resultant force acting on it, a body at rest will remain at rest and a body in motion will continue in motion at constant velocity
state Newton’s Second Law of Motion
rate of change of momentum of a body is proportional to the resultant force acting on the body, and the momentum change takes place in the direction of the resultant force
what does the area under F-t graph represent
impulse / (change in momentum)
define impulse
product of average force and time during which it acts
explain the car safety features
front & rear crumple zones, seatbelts, airbags ➡️ increase amount of time it takes the car to stop so force ⬇️
state Newton’s Third Law of Motion
when body A exerts a force on body B, body B exerts a force of equal magnitude but opposite in direction on body A
what are the characteristics of action-reaction pairs
- equal in magnitude
- opposite in direction
- act on different bodies
- arise from same type of interaction
state the Principle of Conservation of Linear Momentum
when bodies in a system interacts, the total momentum remains constant provided no resultant external force acts on the system
what is a elastic collision
no change in kinetic energy
what is perfectly elastic collision
total momentum, total kinetic energy and total energy are all conserved
what is an inelastic collision
kinetic energy is not conserved
what is a perfectly inelastic collision
the bodies join together after collision
