As per Kepler's third law we know that

now here we know that
= year of Neptune
= year of Earth
= distance of Neptune from Sun
= Distance of Earth from Sun
so now we will have



so length of year of Neptune is 164.3 years
28 times stronger than the force of gravity on the surface of the Earth.
When objects fall to the ground, gravity causes them to accelerate. Acceleration is a change in velocity, and velocity, in turn, is a measure of the speed and direction of motion. Gravity causes an object to fall toward the ground at a faster and faster velocity the longer the object falls
Answer:
time to fall is 3.914 seconds
Explanation:
given data
half distance time = 1.50 s
to find out
find the total time of its fall
solution
we consider here s is total distance
so equation of motion for distance
s = ut + 0.5 × at² .........1
here s is distance and u is initial speed that is 0 and a is acceleration due to gravity = 9.8 and t is time
so for last 1.5 sec distance is 0.5 of its distance so equation will be
0.5 s = 0 + 0.5 × (9.8) × ( t - 1.5)² ........................1
and
velocity will be
v = u + at
so velocity v = 0+ 9.8(t-1.5) ..................2
so first we find time
0.5 × (9.8) × ( t - 1.5)² = 9.8(t-1.5) + 0.5 ( 9.8)
solve and we get t
t = 3.37 s
so time to fall is 3.914 seconds