dynamics Flashcards
Define Newtons first law of motion
an object continues in its state of rest or motion in a straight line unless a resultant external force acts on it
Define Newtons second law of motion
The rate of change of momentum of a body is proportional to the resultant force acting on it and occurs in the direction of the force
Define Newtons third law of motion
If body A exerts a force on body B, body exerts and equal and opposite force on body A
Define mass of an object
The mass of an object is the measure of inertia of an object
Define weight
It is the force experienced by an object in a gravitational field
What are the properties of forces that are an action reaction pair
The two forces must be of the same type
The two forces must be acting on two different bodies and therefore do not cancel each other out
Define linear momentum
The momentum of a body is defined as the product of its mass and its velocity
How is force related to momentum
The rate of change of momentum is directly proportional to the resultant force acting on it ad occurs in the direction of the force.
When no external force, total momentum remains the same
What does impulse mean
It is the product of the force acting on the object and the time for which the force acts
Impulse= Fxt
Impulse also refers to the change in momentum after time t
How is impulse represented graphically
It is the area under the force time graph
What is the principle of conservation of momentum
The principle of conservation of momentum states that when the bodies in a system interact, the total momentum of the system remains constant provided no net external force acts on it
What are the features of an elastic collision
Momentum is conserved
Total energy is conserved
Total kinetic energy is conserved
Relative speed of approach = relative speed of separation
u1-u2= v2-v1
What are the features of an inelastic collision
Momentum is conserved
Total energy is conserved
What are the features of a perfectly inelastic collision
Momentum is conserved
Total energy is conserved
Final velocities are the same as the bodies stick to one another after the collision
What are the features of a super elastic collision
Total momentum conserved
Final KE increases as some potential energy is converted into additional kinetic energy
