There are 5 variables in the equation

*v*= final velocity,

*= initial velocity,*

u

u

*s*= displacement,

*a*= acceleration,

*= time*

t

t

You should be able to solve problems using equation about.

Example :

1. A cyclist accelerates uniformly at 1.2 ms-

^{2 }in 10 s from rest. What is his displacement at this time?

Tips:

- Rest mean zero velocity !!
- You need to know 3 variables to find out the required quantities .

Given;

*u*= 0 ms-

^{1}

*a*= 1.2 ms-

^{2}

*t*= 10 s

*v*= ? ( since

*v is not given you are unable to calculate s using equation 1, 2, 4 and 5)*

*substitute*

*all given information into equation 3*

s= ut+ 1/2 at

s= ut+ 1/2 at

^{2}

*s*= (0) (10) + 1/2 (1.2) (10)

^{2}

=60 m

2. A car approaches a traffic light at 15m/s. The traffic light turns red and the driver applies the brakes at the distance of 25 m from the junction and decelerate at 5 ms-

^{2}. Can the car come to complete stop before reaching the stop line at the traffic light? (ans : yes)

Tips:

- remember to insert the negative sign (-) for decelerate

*learn more in http://en.wikipedia.org/wiki/Equations_of_motion

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