Question 46521
Start by letting P = Potential gravitational energy = mgh.
Let K = kinetic energy = {{{mv^2/2}}}

To answer the question, you should set the potential gravitational energy, P equal to the kinetic energy, K

{{{mgh = mv^2/2}}} Simplify this by dividing both sides by m.
{{{gh = v^2/2}}} Solve for h, the height.
{{{h = v^2/2g}}}

v is the velocity of the car (60 kmph) and you will need to convert this to metres per second.
60 km = 60,000 metres
1 hour = 3,600 secs

So, 60 kmph = 60,000m per 3,600 secs. Simplifying this we get:
v = 16.67 m/sec. Square this for {{{v^2}}}
{{{v^2 = 277.8}}} m^2/sec^2

g (the gravitational constant of acceleration) is 0.98 m/sec^2
Now you can find the height, h.

{{{h = 277.8/2(0.98)}}}
{{{h = 141.7}}} metres