## Tuesday, 28 February 2012

### Kinematics (Review)

1. Definition:

• Speed - The speed is the distance covered over a period of time measured by distance over time. (km/s, m/s, km/min)
• Distance - The distance is the measurement of how far the length is through space. (10 meters, 1 kilometer, 12 millimeter)
• Displacement total distance travelled - It is the length of how far something is from the start after it has travelled.
• Time - Time is the measurement of how long/duration the object took to travel over a certain distance measured in seconds, minutes or hours.
• Velocity - It is an object moving with a direction.
• Average speed - It is the total distance over the average of the total speeds consisting of different speed.
• Acceleration - Acceleration is how much the speed increases over time. Whereas the symbol is m/s^2.
• Deceleration - Deceleration is how much the speed decreases over time.

2. Formulae (Relationship):

• Speed = Distance/time
An object takes time to cover a certain distance. As the unit of speed is m/s, the formula of speed is distance divided by time.

• Distance - time graph

Distance on the y -axis and time on the x -axis. Distance-time graphs is a way to visually show a collection of data. It allows us to understand the relationships between the data. The y -axis (distance) is the distance in relative to the origin point which is the 0 mark. This distance will change overtime if the object is moving whether the object is moving towards or away from the origin point

• Speed - time Graph

Features of the graphs is that when an object is moving with a constant velocity, the line on the graph will be horizontal. If it has a constant accelerating velocity then the line on the graph will be straight as if on the y -axis it shows a straight line where it stays at a certain point on the y-axis and move on the x- axis it will be a constant velocity as it changes in time but not on the speed axis.

3. Key learning points from the motion detector activity:
• We learnt that speed, distance and time can be represented onto graphs. Distance-time graphs show the distance travelled according to time while a velocity-time graph shows the speed the person travelling according to time.
• We learnt how to use a motion detector. With the sound measuring the distance. We also learnt tips and tricks to manipulate the motion detector without walking.
• We learnt how to incorporate technology into Math. Using TI-Nspire to do plot and learn graphs was very useful.

Done by: Joel, Abiyyu, Desiree, Claire, Daniel and Irfan. (*^▽^*)