(a) 907.5 N/m
The force applied to the spring is equal to the weight of the object suspended on it, so:

The spring obeys Hook's law:

where k is the spring constant and
is the stretching of the spring. Since we know
, we can re-arrange the equation to find the spring constant:

(b) 1.45 cm
In this second case, the force applied to the spring will be different, since the weight of the new object is different:

So, by applying Hook's law again, we can find the new stretching of the spring (using the value of the spring constant that we found in the previous part):

(c) 3.5 J
The amount of work that must be done to stretch the string by a distance
is equal to the elastic potential energy stored by the spring, given by:

Substituting k=907.5 N/m and
, we find the amount of work that must be done:

In your question where as the given vector in the xy plane that has a magnitude of 90 units and a,y component of -41 units. So the vector V, base on my calculation and understanding in the problem, the value if it is (<span>8.88, 41</span>)
Answer:
Explanation:
Given
Ray of light incident on plane making an angle of
with normal
Thus incident angle 
So according to the law of incidence is equal to angle of reflection

thus 
and angle between mirror and reflected ray 
