Answer:
r = 0m is the Minimum distance from the axis at which the block can remain in place wothout skidding.
Explanation:
From a sum of forces:
where Ff = μ * N and 
N - m*g = 0 So, N = m*g. Replacing everything on the original equation:
(eq2)
Solving for r:

If we analyze eq2 you can conclude that as r grows, the friction has to grow (assuming that ω is constant), so the smallest distance would be 0 and the greatest 1.41m. Beyond that distance, μ has to be greater than 0.83.
B would be an example of vaporization (liquid to gas).
———————
A is an example of deposition (gas to solid); C is an example of condensation (gas to liquid); and D is an example of condensation, deposition, or freezing—depending on the type of cloud.
The x- and y-coordinates are 9142.57 m and -304.425 m
<u>Explanation:</u>
As the motion of the shell is in a plane (two dimensional space) and the acceleration is that due to gravity which is vertically downward, we resolve initial velocity of the shell
in horizontal and vertical directions. If the initial velocity of the shell is making angle with the horizontal, the horizontal component of initial velocity will be

As the acceleration of the shell is vertical having no horizontal component, the shell may be considered to move horizontally with constant velocity of
and hence the horizontal distance covered (or the x coordinate of the shell with point of projection as origin) is given by


For motion with constant acceleration, we know

Along the horizontal, x-axis, we might write this as

Measuring distances relative to the firing point means

we know that,

or,

By applying the values, we get,

The acceleration of gravity is vertically downward and is
, hence the vertical distance covered (or y coordinate of the shell) is given by the second equation of motion

we know,
and
, so,

y = 11701.8 - 4.9(2450.25)= 11701.8 - 12006.225 = - 304.425 m
This question is incomplete, the complete question is;
Two plane mirrors intersect at right angles. A laser beam strikes the first of them at a point 11.5 cm from their point of intersection, as shown in the figure.
For what angle of incidence at the first mirror will this ray strike the midpoint of the second mirror (which is 28.0 cmcm long) after reflecting from the first mirror
Answer: angle of incidence is 39.4°
Explanation:
Given that;
two plain mirrors intersect at right angle (90°)
distance d = 11.5 cm
S = 28.0 cm
Now the angle that the reflection ray males with first the mirror equal theta (∅)
so
tan∅ = (S/2) / d
tan∅ = (28/2) / 11.5
tan∅ = 14 / 11.5
tan∅ = 1.2173
∅ = tan⁻¹ (1.2173)
∅ = 50.6°
so angle of incidence = 90° - ∅
= 90° - 50.6°
= 39.4°
Therefore angle of incidence is 39.4°
D. The atomic mass in amu is basically the number or nuclei since the mass of the electrons is negligible. For a given atom (element) the number of protons is fixed. Say the element has 10 protons. If the atomic weight is 14 atomic mass units (amu), you know that there are 4 neutrons, since both neutrons and protons are 1 amu each and there are 10 protons