P1. Motion
P1-1: Define speed and calculate speed from (total distance /
total time)
total time)
P1-3 Plot and interpret a speed/time graph and a distance/time graph
P1-4 Recognise from the shape of a speed/time graph when a
body is:
• at rest
• moving with constant speed
• moving with changing speed
body is:
• at rest
• moving with constant speed
• moving with changing speed
Motion graph summary
On a displacement-time graph …
On a velocity(speed)-time graph …
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P1-8 Demonstrate a qualitative understanding that acceleration
is related to changing speed.
is related to changing speed.
When velocity is changing, the word acceleration is used. Acceleration is also a vector. You speed up if the acceleration and velocity point in the same direction. You slow down (also referred to as decelerating) if the acceleration and velocity point in opposite directions. When you accelerate or decelerate, you change your velocity by a specific amount over a specific amount of time.
P1-2: Distinguish between speed and velocity
P1-5 Recognise linear motion for which the acceleration is
constant and calculate the acceleration
P1-6 Recognise motion for which the acceleration is not
constant
P1-7 Calculate the area under a speed/time graph to work out
the distance travelled for motion with constant
acceleration
constant and calculate the acceleration
P1-6 Recognise motion for which the acceleration is not
constant
P1-7 Calculate the area under a speed/time graph to work out
the distance travelled for motion with constant
acceleration
Acceleration
In everyday language we use 'accelerate' to mean speeding up and 'decelerate' to mean slowing down. In scientific terms 'acceleration' is the rate at which something changes its speed - faster or slower.
Acceleration depends on two things:
Calculating acceleration
acceleration = change in speed / time taken
Example- A bus accelerates from 5 m/s to 25 m/s in 10s
To calculate its acceleration, first find the change in speed.
This is 25m/s - 5m/s = 20m/s
Acceleration = 20m/s ÷ 10s = 2m/s2
In everyday language we use 'accelerate' to mean speeding up and 'decelerate' to mean slowing down. In scientific terms 'acceleration' is the rate at which something changes its speed - faster or slower.
Acceleration depends on two things:
- How much the speed changes
- How much time the change in speed takes
Calculating acceleration
acceleration = change in speed / time taken
Example- A bus accelerates from 5 m/s to 25 m/s in 10s
To calculate its acceleration, first find the change in speed.
This is 25m/s - 5m/s = 20m/s
Acceleration = 20m/s ÷ 10s = 2m/s2