Explanation:
Given that,
Initial speed of the rock, u = 30 m/s
The acceleration due to gravity at the surface of the moon is 1.62 m/s².
We need to find the time when the rock is ascending at a height of 180 m.
The rock is projected from the surface of the moon. The equation of motion in this case is given by :

It is a quadratic equation, after solving whose solution is given by:
t = 7.53 s
or
t = 8 seconds
(e)If it is decending, v = -20 m/s
Now t' is the time of descending. So,

Let h' is the height of the rock at this time. So,

or
h' = 155 m
Answer:
It remains the same.
Explanation:
During physical change, the mass, number of atoms and number of molecules will remain the same.
Answer: False
Explanation: They can see it by karst topography!
Answer:
I believe the answer is B.
Explanation:
Newton's First Law of Gravity states, "The greater the weight (or mass) of an object, the more inertia it has. Heavy objects are harder to move than light ones because they have more inertia.
"