Answer:
24.71cm
Explanation:
We approach this problem base don Hooke's law which states the elongation produced in an elastic material is proportional to the applied load or force provided that its elastic limit is not exceeded. This is expressed mathematically as follows;

where F is the applied force, k is the force constant and e is the elongation or extension of the material.
In this problem, the applied force F is the weight of the wood which is calculated as follows,

m = 4.11kg

Hence,

Given that k = 163N/m, we make appropriate substitutions into equation (1) to obtain the following;

Since it is required in cm, we perform the conversion as follows, knowing that 100cm = 1m

NB: We do not necessarily need the the density of the wood to perform our calculations since other parameters were given from which we were able to obtain its weight.
Answer:

Explanation:
Mass of the Sun, 
The radius of the Sun, 
We need to find the acceleration due to gravity on the surface of the Sun. It is given by the formula as follows :

So, the value of acceleration due to gravity on the Sun is
.
Answer:
0.25
Explanation:
Magnification = image distance/object distance
mag = v/u.................. Equation 1
Given: f = -10 cm ( diverging lens) u = 30 cm.
Where can calculate for the value of v using
1/f = 1/u+1/v
make v the subject of the equation
v = fv/(u-f)..................... Equation 2
Substitute into equation 2
v = -30(10)/(30+10)
v = -300/40
v = -7.5 cm.
substituting into equation 1,
mag = 7.5/30
mag = 0.25
hence the magnification of the wretch = 0.25