Question

If ${v^2} = {u^2} + 2as$ solve for $v$ and find the value of $v$ , if $u = 0,a = 2,s = 100.$

Answer 1

Hint- The initial conditions are given in the question, substitute the value of u, a, s and simplify for v.

The given quadratic equation is ${v^2} = {u^2} + 2as$
Since we have all the unknown values given in the question so directly substituting.
Substitute $u = 0,a = 2,s = 100$ and further simplify, we get
$
   \Rightarrow {v^2} = {u^2} + 2as \\
   \Rightarrow {v^2} = {0^2} + 2 \times 2 \times 100 \\
   \Rightarrow {v^2} = 400 \\
   \Rightarrow v = \sqrt {400} \\
   \Rightarrow v = \pm 20 \\
 $
Hence, the value of $v$ is $ \pm 20.$

Note- For solving these types of problems remember the number of unknown variables is equal to the number of equations. So, first find the conditions or initial values that are given in the question and then simplify for unknown variables. The following equation is one of the laws of motion.