A body accelerates uniformly from rest at 2{ms}^{-2}. Calculate its velocity when it has travelled a distance of 9m.

Correct Answer is : 6.0ms−1{ms}^{-1}ms−1

Correct Answer is : 6.0ms−1{ms}^{-1}ms−1

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WAEC Physics 2017 Paper

Question : 3

Total: 50

\mathrm{ms}^{-2}

Solution:

Concept:

Use the equation of uniformly accelerated motion that relates initial velocity, acceleration, distance, and final velocity.

Explanation:

The body starts from rest, so initial velocity

u = 0\,\mathrm{ms}^{-1}

Given acceleration

a = 2\,\mathrm{ms}^{-2}

and distance

s = 9\,\mathrm{m}

Apply the equation:

v^2 = u^2 + 2as

Substitute the values:

v^2 = 0^2 + 2(2)(9)

v^2 = 36

Taking the positive square root:

v = 6.0\,\mathrm{ms}^{-1}

Answer:

6.0\,\mathrm{ms}^{-1}

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