Answer:
Explanation:
Exact numbers are those numbers which are known with 100% certainty or accuracy . Numbers having decimal are generally not exact because they are a part of long drawn decimal number after rounding off to certain places after decimal.
On the basis of this definition we can say as follows
speed of light is 2.99792 ×108 . Here the number quoted is not an exact number because it is a rounded off figure of speed of light to five digits after decimal .
Similarly density of mercury too is rounded off to two digits after decimal
so it is also not a exact number.
There are 3600 s in 1 h . Here 3600 s is an exact number because one hour has been defined as 3600 s . It is not measured by any instrument.
In 2003, the United States had 50 states. Here 50 is an exact number .
Answer:

45.03681 m/s²
Explanation:
= Buoyant force
W = Weight of the balloon
= Density of air = 1.23 kg/m³
= Density of balloon = 0.22 kg/m³
= Volume of air
= Volume of balloon


g = Acceleration due to gravity = 9.81 m/s²
The net force acting on the balloon is

The equation is 

The acceleration of the balloon is 45.03681 m/s²
Answer:
length of column is 140.42 m
Explanation:
in 1 min the soldiers travels 114 steps
so to complete 1 step the time taken by the soldiers =
t = 
t =
t = 0.526 s
speed of sound = 343 m/s
length of the column = v × t
= 343 m/s × 0.526 s
= 140.42 m
hence the length of column is 140.42 m
Kinetic Energy = (1/2) mv^2.
m = 57.7 g = 57.7/1000 = 0.00577 kg.
v = 325 m/s.
E = 0.5 * 0.00577 * 325^ 2. Use your calculator.
E = 304.728125 J.
That's the kinetic energy.
The substance is DNA and it would be found in the nucleus.