Answer:
3.21 grams
Step-by-step explanation:
First we are finding the radioactive decay constant using the formula:
lambda = 
where
lambda is the radioactive decay constant.
is the half life of the radioactive substance.
We know from our problem that Rutherfordium- 265 has a half-life of 13 hours, so let's replace the value in our formula.
lambda = 
lambda = 0.0533 per hour
Now we can use the decay formula to find the remaining quantity of the substance:
where
is the ending amount
is the beginning amount
is the time (in hours)
We know from our problem that there is a 149g sample of Rutherfordium- 265 left at 12am on October 19th, so 
. Notice that there are exactly 3 days from 12 am October 19th to 12 am October 22nd, so we have 
; therefore 
. Now we can replace all the values in our formula:
We can conclude that 3.21 grams of Rutherfordium- 265 would remain on October 22nd at 12 am.
Answer:
3 is the answer 1 + 2 is the same as 1 + 1 + 1=3
hope this helps
have a good day :)
Step-by-step explanation:
Answer: Polyhedron
Step-by-step explanation: A polyhedron is a shape, with 2 parts. Face and Edge, they can only be connected with a edge or a vertex. Only 5 regular polyhedrons exist; tetrahedron ~ 4 faced 'the cube' ~ 6 faced the octahedron ~ 8 faced ~ the dodecahedron ~ 12 faced, and the icosahedron ~ 20 faced.
Given:
A composed figure of a rectangle, semicircle and another semicircle removed.
To find:
The area of the given figure.
Solution:
From the given figure it is clear that the diameter of semicircle and removed semicircle are same, i.e. 8 cm.
Since the diameter of semicircle are equal, therefore their area is also equal.
The area of the given figure is:
A = Area of the rectangle - Area of removed semi circle + Area of semicircle
A = Area of the rectangle - Area of semicircle + Area of semicircle
A = Area of the rectangle
We know that, the area of a rectangle is
The length of the rectangle is 14 units and width is 8 units. So, the area of composed figure is
Therefore, the area of the combined figure is 112 sq. units.
7n + 2 = 4 + 17
7n = -2 + 4 + 17
7n = 19
n = 19/7
your answer is 19/7 (or 2.71)
