Zusammenfassung der Ressource
Physics: Kinematics
- Definition of terms
- Distance: a physical unit that describes how far an object is or describes
the length an object has covered during its motion. (scalar quantity)
- Displacement: the distance travelled along a specified
direction. (vector quantity)
- Speed: the distance moved per unit of time taken. (scalar quantity)
- Average speed: total distance / total time taken
- Velocity: the rate of change of displacement (vector quantity)
- Average velocity: total displacement moved / total time taken
- Acceleration: rate of change of velocity (vector quantity)
- An object that has an equal increase in velocity per unit of time
has constant/uniform acceleration.
- A scalar quantity only has magnitude
- A vector quantity has magnitude and direction.
- Kinematics equations
- are used in situations in which the object has
uniform acceleration and is travelling in a straight
line. (one-dimensional motion/ rectilinear motion)
- v = u + at
- s = 1/2(v+u)t
- s = ut + 1/2at^t
- s = vt - 1/2at^2
- v^2 = u^2 + 2as
- where: v=final velocity,
u=initial velocity,
s=displacement, a=acceleration,
t=time
- Projectile motion (two-dimensional motion)
- for displacement calculation, use the
kinematic equation--s = ut + 1/2at^2
- x-axis displacement: s = ut (no acceleration in horizontal motion)
- y-axis displacement: s = 1/2gt^2
- for velocity calculation, use the
kinematic equation--v = u + at
- x-axis velocity: v = u
- y-axis velocity: v = gt
- At maximum height, the velocity of the y-axis is 0.
- for resultant velocity, use the Pythagoras Theorem
- to find the angle of resultant velocity (between the horizontal velocity
and resultant forces), use trigonometry (tan__(tither) = Vy/Vx