Kinematics | 9702 Physics Summary Notes

• 3. Kinematics | 9702 Physics Summary Notes

3.1 Linear Motion

·  Distance: total length moved irrespective of direction

·  Displacement: distance in a certain direction

·  Speed: distance traveled per unit time, no direction

·  Velocity: the rate of change of displacement

·  Acceleration: the rate of change of velocity

·  Displacement-time graph:

o Gradient = velocity

3.2 Non-linear Motion

·  Velocity-time graph:

o Gradient = acceleration

o Area under graph = change in displacement

·  Uniform acceleration and straight line motion equations:

                 

                    

·  Acceleration of free fall = 9.81ms^-2

3.3 Determining Acceleration of Free Fall

·   

A steel ball is held on an electromagnet.

·  When electromagnet switched off, ball interrupts a beam of light and a timer started.

·  As ball falls, it interrupts a second beam of light & timer stopped

Vertical distance  is plotted against t^2

3.4 Motion of Free Falling Bodies

3.5 Projectile motion

·  Projectile motion: uniform velocity in one direction and constant acceleration in perpendicular direction 

·  Horizontal motion = constant velocity (speed at which projectile is thrown)

·  Vertical motion = constant acceleration (cause by weight of object, constant free fall acceleration)

Curved path – parabolic (y ∝ x²)

3.5 Motion of a Skydiver