Mechanics Flashcards
Define Scalar.
A quantity that has only magnitude.
Define Vector.
A quantity that has magnitude and direction.
3 conditions for an object in equilibrium?
not accelerating (stationary or at a constant velocity)
no resultant force
sum of ACW = sum of CW
What is a moment?
force multiplied by the perpendicular distance from the line of action
What is meant by a couple
A pair of equal and opposite coplanar forces.
What is meant by the centre of mass?
The point through which all the mass of an object acts, for a uniform object the centre of mass is the centre of the object
As speed increases, so air resistance …
Increases (proportional to the square of the speed).
How do the SUVAT equations reflect that all objects fall at the same rate?
Mass is not included in the SUVAT equations, showing that the mass of an object does not affect its speed or acceleration.
In projectile motion, what is the vertical acceleration?
The vertical acceleration is equal to gravitational field strength (g)
projectile motion? vertical acc?
The vertical acceleration is equal to gravitational field strength (g)
What is meant by friction?
A resistance to motion between an object and a surface or an object moving through a fluid. Friction is a force that acts in the opposite direction to the movement.
What is Newton’s first law?
An object stays moving at a constant velocity until a force acts upon it.
What is Newton’s second law?
F = ma
What is Newtons third law?
If object A exerts a force on object B the object B exerts an equal but opposite force on object A
What is the difference between elastic and inelastic collisions?
elastic - momentum and Ek is conserved
inelastic - momentum is conserved, Ek is NOT conserved.
