Answer:
The frictional torque is 
Explanation:
From the question we are told that
The mass attached to one end the string is 
The mass attached to the other end of the string is 
The radius of the disk is 
At equilibrium the tension on the string due to the first mass is mathematically represented as
substituting values
At equilibrium the tension on the string due to the mass is mathematically represented as
The frictional torque that must be exerted is mathematically represented as
substituting values
a 10 kg block reaches a point with a velocity of 15 m per second and slides down a rough track my the coefficient of the kinetic energy between the two surface ab and the block iis0.52
The gravitational potential energy of the system will decreases from 1,250 J to 625 J. Option A is corect.
<h3>What is the law of conservation of energy?</h3>
According to the Law of Conservation of Energy, energy can neither be created nor destroyed, but it can be transferred from one form to another.
The total energy is the sum of all the energies present in the system. The potential energy in a system is due to its position in the system.
TE=KE+GPE
Case 1;
1450 = 200 J+GPE
GPE=1450 -200
GPE=1250 J
Case 2;
1450 = 825 J+GPE
GPE=1450 -825
GPE=625 J
The gravitational potential energy of the system will decreases from 1,250 J to 625 J.
Hence, option A is corect.
To learn more about the law of conservation of energy, refer to brainly.com/question/2137260.
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Before swinging, T has only potential energy, (no speed)
Ui = mgh
Where h is the vertical displacement of T
From the laws of geometry,
cos45 = (L-h)/L
cos45 = 1-h/L
h/L = 1-cos45
h = L(1-cos45)
Therefore
Ui = mgL(1-cos45)
Proceeding the same way,
Twill raise to aheight of h' due to swing
h' = L(1-cos30)
The PE of T after swing is
Uf = mgh'
Uf = mgL(1-cos30)
Along with the PE , T has some kinetic energy results due to the moment.
Tf = 0.5*mv^2
According to the law of conservation of energy,
Ui = Uf+Tf
mgL(1-cos45) = mgL(1-cos30) + 0.5*mv^2
gL(co30-cos45) = 0.5*v^2
9.8*20*(co30-cos45) = 0.5*V^2
v = 7.89 m/s
<span>The speed f T after swing is 7.89 m/s</span>
