Answer:
Work done = 13605.44
Explanation:
Data provided in the question:
For elongation of 2.1 cm (0.021 m) work done by the spring is 3.0 J
The relation between Energy (U) and the elongation (s) is given as:
U =
................(1)
where,
k is the spring constant
on substituting the valeus in the above equation, we get
3.0 = 
or
k = 13605.44 N/m
now
for the elongation x = 2.1 + 4.1 = 6.2 cm = 0.062 m
using the equation 1, we have
U = 
or
U = 26.149 J
Also,
Work done = change in energy
or
W = 26.149 - 3.0 = 23.149 J
Answer:
45.88297 m
Violet
Explanation:
x = Gap between holes = 5.9 mm
= Wavelength = 527 nm
D = Diameter of eye = 5 mm
L= Distance of observer from holes
From Rayleigh criteria we have the relation

A person could be 45.88297 m from the tile and still resolve the holes
Resolving them better means increasing the distance between the observer and the holes. It can be seen here that the distance is inversely proportional to the wavelength. Violet has a lower wavelength than red so, violet light would resolve the holes better.
Answer:

Explanation:
The maximum velocity of an object moving in a curve beyond which it will slide off the curve is given by the relationship in equation (1);

where
is the coefficient of friction between the object and the surface of the curve, g is acceleration due to gravity and r is the radius of the curve.
Given;
v = 0.8m/s
g = 
r = ?

In order to solve for
, we can simply make it the subject of formula from equation (1) as follows;

since we were not given the value of r, we can just substitute other known values, then solve and leave the answer in terms of r.
Therefore;


'A' is correct. B, C, and D are false statements.