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Mechanics Chapter 2 :: �Variable Acceleration

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Functions of time

Up to now, the acceleration has always been constant in any particular period of time…

constant deceleration

no acceleration

constant acceleration

 

time

velocity

time

velocity

 

 

 

 

a

b

?

?

 

 

2

6

24

 

(4,-8)

a

b

c

d

?

?

?

?

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Exercise 2A

Pearson Mechanics 2

Page 27

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Using Differentiation

 

 

 

and similarly…

velocity is the rate of change of displacement

acceleration is the rate of change of velocity

?

?

 

 

 

 

 

 

 

 

?

?

?

a

b

c

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Test Your Understanding

 

 

?

a

b

c

?

?

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Exercise 2B

Pearson Mechanics 2

Page 30-32

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Maxima and Minima Problems

 

 

 

 

 

 

 

 

a

b

?

?

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Test Your Understanding

 

 

?

?

a

b

Edexcel M2 June 2013 Q3a,b

?

?

a

b

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Exercise 2C

Pearson Mechanics

Page 34-36

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Using Integration

Differentiating (with respect to time) gets us from displacement to velocity, and from velocity to acceleration.

So naturally, integrating (with respect to time) gets us from acceleration to velocity, and from velocity to displacement. As mentioned earlier, it’s helpful to picture the graph on the left, where we move down to differentiate and up to integrate.

 

 

Recall in Pure Year 1 that we can find the constant of integration by using known values.

a

b

?

?

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Further Example

 

 

 

 

 

 

?

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Further Example

Edexcel M2 June 2015 Q6

 

a

b

c

?

?

?

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Exercise 2D

Pearson Mechanics 2

Page 38-39

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Constant acceleration formulae

 

 

 

 

 

?

?

a

b

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Exercise 2E/2F

Pearson Mechanics 2

Pages 42-43

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The End