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Concept Map
Measurement of Time and Motion
two main topics
Time
includes
Ancient devices · Pendulum · Second (s)
Speed & Motion
includes
Speed = D÷T · Uniform · Non-uniform
key formula
Speed = Distance ÷ Time
Mind Map
Measurement of Time & Motion
Chapter 8 · Class 7 Science
8.1
Measurement of Time
Sundial · Water clock (2 types) · Hourglass · Candle clock · All use a steady repeating process
8.1.1
Simple Pendulum
Bob · Mean position · Extreme positions · Oscillation · Time period depends only on length
8.1.2
SI Unit of Time
Second (s) · 60 s = 1 min · 60 min = 1 h · Always lowercase · Space before unit
8.2
Slow or Fast
More distance in same time = faster · Speed quantifies how fast an object moves
8.3
Speed
Speed = D ÷ T · SI unit m/s · Also km/h · Multiply m/s by 3.6 for km/h
8.4
Uniform & Non-uniform Motion
Uniform: constant speed, equal distances · Non-uniform: changing speed, unequal distances
Key Terms and Definitions
- Sundial
- It is a device that tells time using the shadow of an object cast by the Sun.
- Pendulum
- It is a bob suspended by a thread from a rigid support that swings back and forth.
- Mean Position
- It is the resting position of the pendulum bob when not swinging.
- Oscillation
- It is one complete back-and-forth movement of the pendulum (O → A → B → O).
- Time Period
- It is the time taken by a pendulum to complete one oscillation. It depends only on the length.
- Second (s)
- It is the SI unit of time. Symbol: s (lowercase). 60 s = 1 min; 60 min = 1 h.
- Speed
- It is the distance covered by an object in a unit time. Formula: Speed = Distance ÷ Time. SI unit: m/s.
- Average Speed
- It is the total distance covered divided by the total time taken over an entire journey.
- Uniform Linear Motion
- It is motion along a straight line at constant speed where equal distances are covered in equal time intervals.
- Non-uniform Linear Motion
- It is motion along a straight line where speed changes and unequal distances are covered in equal time intervals.
- Speedometer
- It is a vehicle instrument that displays the current speed in km/h.
- Odometer
- It is a vehicle instrument that shows the total distance travelled in km.
