The gravity is pushing rhe boat down
One light-year is the distance that light travels in vacuum
in one year. It's a unit of distance.
data which is expressed in form of following way

here in above expression
= true value
= uncertainty in the value
now the relative uncertainty is given as

now by above formula we can say
a) 2.70 ± 0.05cm
here
True value = 2.70
uncertainty = 0.05
Relative uncertainty =
= 0.0185
b) 12.02 ± 0.08cm
here
True value = 12.02
uncertainty = 0.08
Relative uncertainty =
= 0.00665
Answer:
Neap tides, which also occur twice a month, happen when the sun and moon are at right angles to each other. ... This occurs twice each month. The moon appears new (dark) when it is directly between the Earth and the sun. The moon appears full when the Earth is between the moon and the sun.