Answer:
The maximum length of the specimen before deformation is 240.64 mm
Explanation:
Strain = stress ÷ elastic modulus
stress = load ÷ area
load = 2130 N
diameter = 3.4 mm = 3.4×10^-3 m
area = πd^2/4 = 3.142 × (3.4×10^-3)^2/4 = 9.08038×10^-6 m^2
stress = 2130 N ÷ 9.08038×10^-6 m^2 = 2.35×10^8 N/m^2
elastic modulus = 126 GPa = 126×10^9 Pa
Strain = 2.35×10^8 ÷ 126×10^9 = 0.00187
Length = extension ÷ strain = 0.45 mm ÷ 0.00187 = 240.64 mm
The SI base units for length is meter (m) and for time is seconds (s).
The given ratio is 

Converting mm/s to m/s as:
Since, 1 mm/s = 0.001 m/s
So, 
Since, zeroes to the left side of the non-zero number are not significant hence, the evaluation of
to three significant figures and answer in SI units is
.
Answer:
C or D
Explanation:
Hope it helped a little bit
17) 8.4 / 20 x 100
18) 20 . 0.5150
19) 6,50% because (as you said) the law of definite proportions states that regardless of the amount, a compound is always composed of the same elements in the same proportion by mass