Mechanics 2 Flashcards
When may suvat be used?
when the acceleration is constant
What is Newton’s first law of motion?
an object remains in uniform motion unless acted on by a resultant force
What is meant by uniform motion?
constant velocity
What is Newton’s 2nd law of motion?
the acceleration of an object is directly proportional to the resultant force that acts on it
What is Newton’s third law of motion?
if object A exerts a force on object B, then object B exerts an equal and opposite force on object A
What is meant by ‘weightlessness’?
the only force acting on an object is its weight
What is meant by freefall?
When the only force acting on an object is its weight, and it accelerates at g
What path do projectiles follow and why?
- parabolic
- due to constant horizontal velocity and constant vertical acceleration
Define terminal velocity
the velocity at which driving forces match the frictional forces
What is the relationship between terminal velocity and drag?
- drag is directly proportional to terminal velocity squared
- drag = k(v)^2
Why is drag directly proportional to terminal velocity squared?
- when v doubles, there are twice as any collision with air molecules
- each collision is twice as hard
What does k relate to in the equation drag = k(v)^2?
related to the surface area
For a falling object at terminal velocity, what does drag equal?
the weight of the object
What happens to drag as speed increases?
drag also increases
