A bob sled at the winter Olympics slides down the frictionless run

which dips and flattens and twists and turns. The speed at some point

is v$.$ At a lower point it is $4$v$.$ The vertical distance between these

points is:

$($a$)$ g

v

$.$

$2$

$50($b$)$ g

v

$.$

$2$

$57($c$)$ g

v

$.$

$2$

$51($d$)$ g

v

$.$

$2$

$53($e$)$ g

v$2$