Pages Covered - 34-37

• Acceleration Formula

  • Its change in velocity (how much it speeds up)

  • The time taken (how long it takes to speed up

  • A = Change in velocity / Change in time

    
    
    
    

• Unit Of Acceleration

  • The Unit Of acceleration is M/S square

  
  

• Acceleration From Speed-Time Graph

  • The object must be travelling in a straight line; its velocity is changing but its direction is not.

  • If the speed–time graph is curved (rather than a straight line), the acceleration is changing.

  • If the graph is sloping downwards, the object is decelerating. The gradient of the graph is negative. So a deceleration is a negative acceleration.

    
    
    
    

• Example Of Calculating Acceleration

  • A car sets off from traffic lights. It reaches a speed of 21 m/s in 10 s. What is its acceleration?

  • A = V - U / T

  • A = 21 - 0 / 10

  • = 21/10

  • = 2.1 m/s

• Calculating Speed in Distance-Time Graph

  • Formula : Speed = Gradient Of Distance–Time Graph

  • Example

• Speed = 80/1

• Speed = 80 km/h