Consider this case: A ball is allowed to fall freely with a constant acceleration of 10 m/s^2. What will its speed be after travelling a distance of 10 m?(adsbygoogle = window.adsbygoogle || []).push({});

We get that:

v[initial] = 0 m/s

d = -5 m (downward direction is taken as negative)

a = -10 m/s^2

To find v[final], we will use the formula d = (v[final]^2-v[initial]^2) / (2a)

Rearranging, we will get:

v[final]^2 = 2ad + v[initial]^2

By plugging the numbers, we will get:

v[final]^2 = 100 m^2/s^2

By mathematics, there are 2 solutions to this problem, that is v[initial][1] = +10 m/s and v[initial][2] = -10 m/s. I can only think of the situation where the ball has a downward velocity. Is the other answer (the one with +10 m/s velocity) possible/does it has a physical reality? If so, can anyone explain the situation? Thanks a lot!

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# Physical Significance of Numbers

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