can someone explain why the answer is B? (1 Viewer)

[waltssillyhat]

this is from the kinematics chapter review in the yr 11 pearson textbook

 

[cheesynooby]

all grav potential energy is converted to kinetic energy (conserv. of energy)
so U = mgh = (1/2)mv^2 = K
v = sqrt(2gh)
so when h is doubled (x2) v increases by sqrt(2)