A particle starts from rest and moves in a straight line such that its velocity,...

FURTHER MATHEMATICS
WAEC 2019

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.

  • A. 12m
  • B. 16m
  • C. 64m
  • D. 96m

Correct Answer: B. 16m

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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