Question

Where v is the final velocity (in m/s), u is the initial velocity (in m/s), a is the acceleration (in m/s²) and s is the distance (in meters).

Find v when u is 9 m/s, a is 7 m/s², and s is 28 meters.

Answer 1

The final velocity v is 21.74 m/s.

Explanation:

Given:

`\textrm{initial velocity} = u = 9\ m/s\\\textrm{acceleration} = a = 7\ m/s^(2)\\\textrm{distance} = s = 28\ m`

To find:

`\textrm{final velocity} = v = ?`

Solution:

As we know the third equation of motion is represented as

`v^(2) = u^(2) + 2* a* s\\`

Substituting the values u, a and s in the above equation we get

`v^(2) = 9^(2) + 2* 7* 28\\ =81 + 392\\=473\\`

`v =\±√(473) \\v =√(473) \ \textrm{as acceleration is positive v is also positive}\\v = 21.74\ m/s`