Which literal equations are equivalent to f = ma?
a.) m= f x a
b.) m= f/a
c.) a= m/f
d.) a= f/m

The answers to the question above are letters B and D. For the first answer, m = F/A, if we cross multiply the terms, we get mA = F which is similar to the given expression. For the next answer, A = F/m, we also get Am = F if we do cross multiplication. 

Kinetic energy = 1/2mv^2. since the mass is constant we can form a ratio of it's kinetic energy at 60 divided by that at 30 to see ke(60)/ke(30) = +(60^2)/30^2). this may be said to 300% increase.