To solve this problem it is necessary to apply the kinematic equations of motion.
By definition we know that the position of a body is given by

Where
Initial position
Initial velocity
a = Acceleration
t= time
And the velocity can be expressed as,

Where,

For our case we have that there is neither initial position nor initial velocity, then

With our values we have
, rearranging to find a,



Therefore the final velocity would be



Therefore the final velocity is 81.14m/s
By looking at how wiggily the bar is lol
The answer is: [C]: "4" .
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Note: To balance this equation, the coefficient, "4", should be placed in front of the PCl₃ ; and the coefficient, "6", should be placed in front of the Cl₂ .
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The balanced equation is:
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P₄ (s) + 6 Cl₂ (g) <span>→ 4 </span>PCl₃ (l) .
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The kinetic energy (KE) is 250 J and the gravitational potential energy (GPE) is 392 J