WEBVTT

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Here is the problem: Starting at 0 m/s, an object covers 45 m in 3 s with constant acceleration. Find its final speed and acceleration.

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Find final velocity v and acceleration a for motion in a straight line with constant acceleration.

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List the known quantities. Unknown: final velocity v and acceleration a.

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Acceleration from the displacement equation.

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Final velocity.

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So the answer is v equals 30 m/s, a equals 10 m/s squared.

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With constant acceleration, any three of displacement, initial velocity, final velocity, acceleration and time fix the other two. Each pair of unknowns is solved with the equation that does not contain the other unknown.

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Check v squared equals u squared plus 2as: 900 equals 900.