Answer:
P = d g h pressure due to density of liquid of height h
d1 g h1 = d2 g h2 since P1 equals P2
d1 h1 = d2 h2 and the density of Hg is 13.6 times that of water
h2 = (d1 / d2) * h1 = 13.6 * 70 cm = 952 cm or 9.52 m
The car will gain new momentum if it's velocity is doubled or tripled.
Actual Mechanical Advantage(AMA) = Weight / Force
Here, Weight = 764 N
Force = 255 N
Substitute the values in to the expression,
AMA = 764 / 255
AMA = 2.99
After rounding-off to the nearest tenth value, it would be 3
Finally, option C would be your answer.
Hope this helps!