##### I need help understanding the kinematic equations and when to use them?

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What is the acceleration of a vehicle that changes its velocity from 200 km/h to a dead stop in 30 s ? Answer in units of m/s 2

Oct 8th, 2015

acceleration = change of velocity ÷time

= (final velocity - inital velocity) ÷ time

We have to change the velocity to m/s first before uding this formula

200 km = 200 × 1000n = 20000m

and 1 hour = 60  × 60 s = 3600 s

So initial velocity = 20000 ÷ 3600 = 50/9 = 5.5556m/s

So accelation = ( 0 - 5.55556 ) ÷ 30

= -0.185185 m/s^2

Oct 8th, 2015

acceleration = change of velocity ÷time

= (final velocity - inital velocity) ÷ time

We have to change the velocity to m/s first before using this formula

200 km = 200 × 1000m = 20000m

and 1 hour = 60  × 60 s = 3600 s

So initial velocity = 20000 ÷ 3600 = 50/9 = 5.5556m/s

So accelation = ( 0 - 5.55556 ) ÷ 30

= -0.185185 m/s^2

Oct 8th, 2015

how would I apply the kinematic equations?

Oct 8th, 2015

Here, the application means

1. knowing the definition and using it

2. changing the units so that you have it in the form required

In general, you may have to decide which equation of motion to use - and that depends on the information given in the question, as well as using 1 and 2 above.

Oct 8th, 2015

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Oct 8th, 2015
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Oct 8th, 2015
Aug 18th, 2017
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