Forces And Motion Vocab Flashcards
Weight
The pull of gravity on an object which has mass - a force
Depends on: -mass of an object
-the size of the gravitational field (which planet you are on)
Newtons (N)
Force on an object that has mass, due to gravitational attraction
W=mg (g=gravitational field strength)
Mass
Measures the resistance of an object to accelerate (changes in motion)
The amount of matter in an object
Never changes
In Kilograms
Displacement
Distance moved from original point
Centre of mass/gravity
The point through which the whole weight of the object seems to act
Equilibrium
Clockwise = anticlockwise No resultant force/motion Balanced Force downwards = force upwards Total moment = 0 Centre of mass directly above/below pivot
Stable object
Doesn’t topple over easily if acted upon by a force
Returns to equilibrium position when force removed
Depends on centre of mass
More stable with larger base and lower centre of mass
Force
A push or pull
Vectors
Newtons (N)
Vector
Both magnitude and direction
Reaction (force)
Force on an object resting on a surface that acts perpendicular to that surface
Tension (force)
Force on a stretched object
Lift (force)
Upward force on the wing of an aeroplane
Friction
Contact force that opposes the motion of one object sliding over another
Air resistance
Frictional force opposing the motion of an object through a fluid
Thrust
Push due to a rocket engine
Up thrust
Buoyancy force acting upwards on an object immersed in a fluid
Resultant force
Overall force with all forces combined (take smaller one away from the larger)
Inertia
Tells how much an object accelerates relating to it’s mass eg. heavier=harder to move
Velocity
Speed and direction of object described
Vector quantity eg. displacement, force
Direction as well as magnitude
Speed
=magnitude of the velocity
Scalar quantity
Terminal velocity
The fastest a falling object can travel at Resultant force=0 Balanced forces No longer accelerates - constant speed Depends on surface area+weight of object Air resistance=weight
Free fall
An object falling without air resistance under the earths gravitational field
Depends on: size, shape and surface area of object
Acceleration
Rate of change in velocity
A=Δv/t
Moment
Turning effect about a pivot
Eg. Opening a door, wheelbarrow etc.
moment=force x perpendicular distance to the pivot
