Do Now

A motorbike accelerates at 2.6 ms-2 for 4 seconds until it reaches the new speed of 25 ms-1.

a) What distance is covered along the course of acceleration?

b) What was the bike’s initial velocity?

Remember - KUFSS

Using Kinematic Equations 2

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WarningThe 5th equation will not appear on the formulae sheet supplied on the examination day.

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Solution: Memorise(hint – notice how the 5th equation looks

strikingly similar to the 4th equation)

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Ponder this:What if a = 0? (no acceleration)

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Question ONE

A rock is dropped from the roof of a 23 m tall building. As it falls, it accelerates at 9.8 ms-2.

a) What is the speed of the rock at the moment it hits the ground?

b) How long does it take to reach the ground?

Remember - KUFSS

Question TWO

A running train decelerates at 1.3 ms-2 then it comes to a stop after 47 s.

a) What distance has the train covered since it started to slow down?

b) At what velocity was the train going before it began to slow down?

Acceleration due to gravity

g = 9.8 ms-2 ↓

ANY object’s motion that is under the influence of the Earth’s gravity, is subject to the acceleration due to gravity = 9.8 ms-2 downwards.

Remember that g could be negative, depending on the frame of reference

Question THREE

Hayden throws his cricket ball perfectly vertically upwards. The ball takes 2.3 seconds to reach its maximum height, then it falls back down.

a) How high does the ball travel up? (ignore Hayden’s height)

b) What is the initial speed of Hayden’s throw?