Answer:
A. 97.8 mm
Explanation:
There are 10 divisions between 9 cm (90 mm) and the end of the ruler (10 cm or 100 mm).
Each division equals 1 mm.
Each 5 mm mark has a longer tick, and the dashed red line is between the 97 mm and 98 mm marks.
You would normally estimate to the nearest tenth of a division. An estimate of 0.8 mm is reasonable.
The length of the object is 97.0 mm + 0.8 mm = 97.8 mm.
B is wrong. You can't possibly estimate to the nearest hundredth of a division.
C is wrong. The dashed red line slightly before the 98 mm mark.
D is wrong. If the dashed red line were exactly on the 98 mm mark, you would record the measurement as 98.0 mm. This indicates that you measured the object to zero tenths on either side of the mark.
Answer:
= 3/4
Explanation:
Half life is the time taken by a radioactove element to decay by half of its original mass.
The half life of tritium is 12.3 years , therefore it would take 12.3 years for tritium to decay to a half its original mass.
Using the formula;
New mass = Initial mass × (1/2)^n ; where n is the number of half lives.
n = 5.2 years/12.3 years
= 52/123
Therefore;
New mass = 1 × (1/2)^(52/123)
= 0.74599
= 0.75
The fraction of a tritium sample after 5.20 years will be approximately 3/4
From your notation, it is phosphorus trichloride. Basically, there are three molecules of phosphorus chloride.
Mass is density times volume
0.760 x 531 = 403.56g
404g if 3 sig figs
Gravity. The rock is being pushed down and you are counteracting that force with a crowbar pushing it upward.
