Question

It's timed plzzz help!!!

Answer 1

Answer:

$D.v= \± \sqrt{\frac{2E}{m}}$

Step-by-step explanation:

$We\ are\ given\ that,\\Kinetic\ Energy\ possessed\ by\ an\ object=\frac{1}{2}mv^2\\Hence,\\E_k=\frac{1}{2}mv^2\\2E=2*\frac{1}{2}mv^2 [Multiplying\ both\ the\ sides\ with\ 2]\\2E=mv^2\\\frac{2E}{m}=\frac{mv^2}{m}[Dividing\ both\ the\ sides\ by\ m]\\\frac{2E}{m}=v^2\\Now,\\As\ v\ could\ be\ positive\ or\ negative\ but\ its\ square(v^2)\ would\ always\ be\ positive.$

$(\± v)^2= v^2\\Hence,\\\frac{2E}{m}= (\±v)^2 \\\sqrt{\frac{2E}{m}} = \±v\\Or,\\ v= \± \sqrt{\frac{2E}{m}}$

Answer 2

Answer:

Last Choice / D

Step-by-step explanation:

you want to isolate v!

E = 1/2 m v^2

multiply both sides by 2

2E = mv^2

divide both sides by m

2E/m = v^2

square root both sides

v = ±$\sqrt{2E/m}$

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