Given: The number = 0.0069 that has to be expressed in scientific notation
Concept: When we express any number in scientific notation then we shall consider two points.
(i) If we shift the decimal point from left to right after first (non-zero) digit then we count the number of shifted place of decimal and write them in terms of the negative power of 10. For example, 0.004789 = 4.789 ×10⁻³
(ii) If we shift the decimal point from right to left after first (non-zero) digit from the left end then we count the number of shifted place and write then in terms of the positive power of 10. For example, 4789.24 = 4.78924 ×10⁺³ = 4.78924 ×10³ Now, we shall convert the given number 0.0069 in scientific notation
0.0069 = 6.9 ×10⁻³ because we have shifted the decimal from left to right for three places that is after digit 6.
Hence, the last option 6.9 ×10⁻³ will be the correct option.
Answer:
The maximum speed of sonic at the bottom of the hill is equal to 19.85m/s and the spring constant of the spring is equal to (497.4xmass of sonic) N/m
Energy approach has been used to sole the problem.
The points of interest for the analysis of the problem are point 1 the top of the hill and point 2 the bottom of the hill just before hitting the spring
The maximum velocity of sonic is independent of the his mass or the geometry. It is only depends on the vertical distance involved
Explanation:
The step by step solution to the problem can be found in the attachment below. The principle of energy conservation has been applied to solve the problem. This means that if energy disappears in one form it will appear in another.
As in this problem, the potential and kinetic energy at the top of the hill were converted to only kinetic energy at the bottom of the hill. This kinetic energy too got converted into elastic potential energy .
x = compression of the spring = 0.89
It lets the viewer know it's something to do with underwater.
Explanation:
(a) Formula to calculate the density is as follows.

= 
= 
Now, calculate the charge as follows.

= 
=
C
or, = 101.06 nC
(b) For r = 6.50 cm, the value of charge will be calculated as follows.

= 
= 7.454 