The mechanical advantage is defined as the ratio between the force produced by a machine and the force applied in input:

For the crowbar of the problem, the force applied in input is 40 N, while the force produced in output is equal to the weight of the rock that is lifted, so 400 N. Therefore, the mechanical advantage is
Answer:
Hello your question is incomplete attached below is the complete question
Answer : x ( acceleration of mass 4m ) = 
The top pulley rotates because it has to keep the center of mass of the system at equilibrium
Explanation:
Given data:
mass suspended = 4 meters
mass suspended at other end = 3 meters
first we have to express the kinetic and potential energy equations
The general kinetic energy of the system can be written as
T = 
T =
also the general potential energy can be expressed as
U = 
The Lagrangian of the problem can now be setup as

next we will take the Euler-Lagrange equation for the generalized equations :
Euler-Lagrange equation = 
solving the equations simultaneously
x ( acceleration of mass 4m ) = 
The top pulley rotates because it has to keep the center of mass of the system at equilibrium
Answer:
fcosθ + Fbcosθ =Wtanθ
Explanation:
Consider the diagram shown in attachment
fx= fcosθ (fx: component of friction force in x-direction ; f: frictional force)
Fbx= Fbcosθ ( Fbx: component of braking force in x-direction ; Fb: braking force)
Wx= Wtanθ (Wx: component of weight in x-direction ; W: Weight of semi)
sum of x-direction forces = 0
fx+ Fbx=Wx
fcosθ + Fbcosθ =Wtanθ
Answer:
The frequency of radiation is 
Explanation:
Given:
Wavelength
m
Speed of light

For finding the frequency of radiation,




Therefore, the frequency of radiation is 