Answer:
the diameter of the outside edge of the receiver is 
Explanation:
From the schematic free body diagram illustrating what the question is all about below;
Let represent A to be the vertex where the receiver is being placed
S to be the focus
BP to be equal to r (i.e radius of the outer edge)
BC to be 2 r (i.e the diameter)
Given that AS = 4 in and AP is 18 in
Let AP be x- axis and AY be y -axis
A=(0,0)
S=(4,0) = (0,0)
So that the equation of the parabolic path of the receiver will be:

B = (AP, BP)
B = (18, r)
B lies y² = 16 x
r² = 16 x
r² 16 × 18

Diameter BC = 2r

Answer:
<em>a) 2.15 m</em>
<em>b) 123 m</em>
<em>c) 772.8 m</em>
Explanation:
<u>Circular Motion</u>
One point located at a distance r from the center of rotation travels a distance L given by the arc length :

Where
is the angle formed during the rotation.
The wheel described in the question has a radius r=4.1 m and a point on the wheel rotates some angles given in each part:
a) 
Calculating L

b) 

c) 

Answer:Answer:
They are inhaled or eaten
Explanation:
Radioactivity can be defined as the process in which an unstable atomic nucleus spontaneously emits ionizing radiation and charge particles. This eventually results in the formation of an energetically stable atomic nucleus.
Examples of radioactive elements are Uranium, Polonium, Thorium, Radon, etc. The radiation emitted during this process is classified as;
1. Alpha radiation (α).
2. Beta radiation (β).
3. Gamma radiation (G).
Alpha-emitting substances, such as radon gas, can be a serious health hazard only if they are inhaled or eaten. Alpha-emitting substances compared to other radiation has very short-range particle and as such cannot penetrate the human skin or body.
Quantum dots are crystals of a fluorescent semiconductor material with a diameter of as few as 10 to 100 atoms. They are used as labels for imaging molecules because of their very narrow fluorescence, brightness, and resistance to photobleaching.
This is the most recent information I could find.
I hope this helps:)