Answer:
What is the problem I cant help unless you have the problem.
Explanation:
 
        
                    
             
        
        
        
Answer:
The focal lenth (F) =+10.0cm
Explanation:
The formular for combined focal length (F) is given as;

In this  question, 
F1 = 20cm
F2  = -30cm
Plugging the values into the formuar above,

![1/f = 0.05 - 0.033[tex]1/f = -0.017f = [tex]1/ -0.017](https://tex.z-dn.net/?f=1%2Ff%20%3D%200.05%20-%200.033%3C%2Fp%3E%3Cp%3E%5Btex%5D1%2Ff%20%3D%20-0.017%3C%2Fp%3E%3Cp%3Ef%20%3D%20%5Btex%5D1%2F%20-0.017)
f = 58.82cm
i.e. the combination behaves as a converging lens (because of the postive sign) of focal length 58.82cm .
 
        
             
        
        
        
Answer:
A)5524J, 
B) 29.2Nm
Explanation:
This question can be treated using work- energy theorem
Work= change in Kinectic energy
W= Δ KE
Work= difference between the final Kinectic energy and intial Kinectic energy.
We know that 
Kinectic energy= 1/2 mv^2 .............eqn(1)
This can be written in term of angular velocity, as
KE= 1/2 I
 
        
             
        
        
        
Answer:
5 Days to Seconds = 432000
Explanation:
 
        
             
        
        
        
Answer:
F₂= 210 pounds
Explanation:
Conceptual analysis
Hooke's law
Hooke's law establishes that the elongation (x) of a spring is directly proportional to the magnitude of force (F) applied to it, provided that said spring is not permanently deformed:
F= K*x   Formula (1)
Where;
F  is the magnitude of the force applied to the spring in Newtons (Pounds)
K is the elastic spring constant, which relates force and elongation. The higher its value, the more work it will cost to stretch the spring. (Pounds/inch)
x the elongation of the spring (inch)
Data
The data given is incorrect because if we apply them the answer would be illogical.
The correct data are as follows:
F₁ =80 pounds
x₁= 8 inches
x₂= 21  inches
Problem development
We replace data in formula 1 to calculate  K :
F₁= K*x₁
K=( F₁) / (x₁)
K=( 80) / (8) = 10 pounds/ inche
We apply The formula 1 to calculate  F₂
F₂= K*x₂
F₂= (10)*(21)
F₂= 210 pounds