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:
Magnitude of angular acceleration = -3.95 rad/s²
Explanation:
Angular acceleration is the ratio of linear acceleration and radius.
That is

Radius = 72 cm = 0.72 m
Linear acceleration is rate of change of velocity.

Angular acceleration

Angular acceleration = -3.95 rad/s²
Magnitude = 3.95 rad/s²
Answer:
True.
Explanation:
A nanometer is a unit of mass, whereas a nanosecond is a unit of time. To convert 1.3 hours to minute, you would multiply by 1 h / 60 min. Kilometer is a unit of length, whereas kilogram is a unit of mass. True.
Answer:
The uncertainty in the location that must be tolerated is 
Explanation:
From the uncertainty Principle,
Δ
Δ

The momentum P
= (mass of electron)(speed of electron)
= 
= 
If the uncertainty is reduced to a 0.0010%, then momentum
= 
Thus the uncertainty in the position would be:
Δ
Δ