WAEC - Further Mathematics (2019 - No. 21)

A particle starts from rest and moves in a straight line such that its velocity, V ms\(^{-1}\), at time t second is given by V = 3t\(^2\) - 6t. Calculate the acceleration in the 3rd second. 
12m
16m
64m
96m

Explanation

V = 3t\(^2\) - 6t

\(\frac{ds}{dt} = 3t^2 - 6t\)

s = \(\int 3t^2 - 6t\)

s = \(\frac{3t^3}{3} - \frac{6t^2}{2} + k\)

s = t\(^3\) - 3t\(^2\) + k

s = 0, t = 0

s = t\(^3\) - 3t\(^2\) 

s = 4\(^3\) - 3t\(^2\) 

s = 4\(^3\) - 3(4)\(^2\) 

= 64 - 48 = 16m

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