1.2 kinematics Flashcards
mean speed
the average rate of change of distance
instantaneous speed
the speed at any given point in time
displacement
shortest distance between initial and final position, together with direction
velocity
rate of change of displacement, or speed given in a direction
mean velocity
average velocity over a specified period of time
instantaneous velocity
the velocity at any given point in time
acceleration
rate of change of velocity
terminal velocity
when the forcing acting on a falling object becomes balanced, the acceleration becomes zero and the object is moving at maximum velocity
When can the xuvat equations by used?
When there is constant acceleration and motion along a straight line.
What is the effect of mass on the acceleration for an object in free-fall?
None
What is the relationship between displacement and time for an object falling freely from rest?
Displacement is proportional to time squared (xαt²)
What is a projectile
An object acted upon only by the force of gravity
What is the initial vertical velocity of an object projected horizontally?
Zero
What is the initial horizontal velocity of a projectile launched at speed u, at an angle of θ to the horizontal?
u cosθ
What is the initial vertical velocity of a projectile launched at speed u, at an angle of θ to the horizontal?
u sinθ
Ignoring air resistance what is the acceleration of a projectile?
Always g downwards
How does horizontal velocity vary in projectile motion?
It is constant
How do the initial and final velocities compare if a projectile returns to its starting height?
They have the same magnitude but opposite direction/sign.
What equation is used to analyze the horizontal component of projectile motion?
Displacement = Velocity x time (since horizontal velocity is constant)
x = (v - u) x t
What aspect links the vertical and horizontal motion of a projectile?
Time taken to fall
Why can XUVAT equations can be used for the vertical component of projectile motion?
The motion is in a single direction with a constant acceleration
What is the vertical velocity at the peak of projectile motion?
Zero
why does a body fall
force of gravity acts on it
