# Physics - Mechanics

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## Mechanics - Kinematics 2.1.1

• Displacement - Distance travelled in a particular direction.
• Velocity - Distance travelled in a certain direction in 1 second.
• Speed - Distance travelled in 1 second.
• Acceleration - The change in velocity in 1 second.
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## Mechanics - Kinematics 2.1.2

• Instantaneous values of speed, velocity and acceleration is the value at a single moment in time, not over a period of time. Average values of all three are the average values of the speed/velocity/acceleration over a certain period of time, not just a single moment.

• Average velocity is the difference between the beginning and the end.
e.g. distance = 16km, journey time = 4 hours
average velocity = 16/4
= 4 km h^-1
• Average velocity = displacement/time

• Average speed = distance/time

• Average acceleration = change in velocity/change in time
unit of acceleration is m s^-2
Acceleration is a vector quantity
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## Mechanics - Kinematics 2.1.3

• The equations of uniformly accelerated motion can only be under conditions where the acceleration is constant.
• SUVAT used for uniformly accelerated motion:
• v = u + at
• s = (u + v/2) t
• v^2 = u^2 + 2as
• s = ut + 1/2at^2
• s = vt - 1/2at^2
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## Mechanics - Kinematics 2.1.6

• Air resistance eventually affects all objects that are in motion. Due to the effect of air resistance objects can reach terminal velocity. This is a point by which the velocity remains constant and acceleration is zero.
• In the absence of air resistance all objects have the same acceleration irrespective of its mass.
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## Physics

• Instantaneous velocity is how fast it’s going at that moment in time and in which direction.
• Average velocity is the difference between the beginning and the end.
e.g. distance = 16km, journey time = 4 hours
average velocity = 16/4
= 4 km h^-1
• average velocity = displacement/time
• Instantaneous velocity = length/time for object to pass
• Acceleration = change of velocity/time
unit of acceleration is m s^-2
Acceleration is a vector quantity
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