The free fall acceleration due to the Earth's gravity will always be 9.8m/s^2. So, if this question is taking place on Earth, then the acceleration of an object in free fall is 9.8m/^2.
Gravitational force is determined by mass
Answer: Option B
<u>Explanation:</u>
According to Universal law of gravity, the gravitational force is directly proportional to the product of the masses of the objects and inversely proportional to the square of the distance between the objects.

Where,
G – gravitational constant = 
= masses of two objects
r – distance between the objects
So, as per this law, the gravitational force is found by mass.
Answer:
Kinematics is the study of motion.
348.34 m/s. When Superman reaches the train, his final velocity will be 348.34 m/s.
To solve this problem, we are going to use the kinematics equations for constant aceleration. The key for this problem are the equations
and
where
is distance,
is the initial velocity,
is the final velocity,
is time, and
is aceleration.
Superman's initial velocity is
, and he will have to cover a distance d = 850m in a time t = 4.22s. Since we know
,
and
, we have to find the aceleration
in order to find
.
From the equation
we have to clear
, getting the equation as follows:
.
Substituting the values:

To find
we use the equation
.
Substituting the values:
