Answer:

Explanation:
The values of the position and velocity of the ball are missing in the text - found the table in internet, see attached picture.
We can solve this problem by using the following SUVAT equation:
v(t) = u +at
where
v(t) is the velocity of the rock at time t
u is the initial velocity
a is the acceleration of gravity on the planet
t is the time
At t = 0, u = 20 m/s.
After 1 second, t = 1 and v = 15 m/s. Substituting these values and solving for a, we find:

And the negative sign means the acceleration is downward.
PE = mgh₁ - mgh₂= 12.5J
h₁ = ?
h₂ = 0
h₁ = PE / mg = 12.5 / 9.8
Answer:
5.28 x 10⁻⁹N
Explanation:
Given parameters:
Mass of alien = 71kg
Distance = 670m
Mass of ship = 500000kg
Unknown:
Gravitational attraction = ?
Solution:
The gravitational attraction can be found using the Universal gravitation law proposed by Newton;
Fg =
G is the universal gravitation constant = 6.67 x 10⁻¹¹
d is the distance
Fg is the gravitational attraction
Fg =
= 5.28 x 10⁻⁹N
Gravity?
I'm not too sure.
If you mean what pulls an object towards the centre of the Earth.