A body of mass 10kg moving with a velocity of 5\(ms^{-1}\) collides with another body of mass 15kg moving in the same direction as the first with a velocity of 2\(ms^{-1}\). After collision, the two bodies move together with a common velocity v\(ms^{-1}\).

  • A 3.2
  • B 5.3
  • C 7.0
  • D 8.0
waec 2016furthermathematics

The correct answer is A. 3.2

Momentum of bodies with common velocity = \(m_{1}v_{1} + m_{2}v_{2} = (m_{1} + m_{2})v\)

\((10 \times 5) + (15 \times 2)  = (10 + 15)v\)

\(50 + 30 = 25v \implies v = \frac{80}{25} = 3.2ms^{-1}\)

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