Answer:
K = 25 joules
Explanation:
given
v =

we require to find K
square both sides to clear the radical
v² =
( multiply both sides by m to clear the fraction )
mv² = 2K ( divide both sides by 2 )
= K
substitute m = 2 and v = 5 into the equation
= K ( cancel 2 on numerator/ denominator on left side )
5² = K , that is
K = 25 joules