Respuesta :
Answer:
The workdone by P is [tex]W_p=2.2J[/tex]
Explanation:
Generally workdone is mathematically represented as
[tex]W = F *d[/tex]
Where F is the force and d is the distance
The total workdone = (Workdone by Force P + Workdone by frictional force )
The difference in kinetic energy
[tex]\Delta KE = KE_2 - KE_1[/tex]
Substituting 5.6 J for [tex]KE_1[/tex] and 4.0 J for [tex]KE_2[/tex]
[tex]\Delta KE = 5.6 - 4[/tex]
[tex]= 1.6J[/tex]
This change in kinetic energy of the block = The total kinetic energy
The workdone by the frictional force is
[tex]W_F = -F_f * d[/tex]
the negative sign shown that the force is moving in the opposite direction
substituting 1.2 N for [tex]F_f[/tex] and 0.5 m for d
[tex]W_F = -1.2*0.5[/tex]
[tex]=-0.6J[/tex]
Making Workdone by Force P the subject in the above equation we
Workdone by Force P ([tex]W_P[/tex]) = The total workdone([tex]W_T[/tex]) - [tex]W_F[/tex]
Substitution values
[tex]W_p = 1.6 -(-0.6)[/tex]
[tex]W_p=2.2J[/tex]
The work done on the block by the force P between A and B is; 2.2 J
In this question, there will be work done by friction and work done by the applied force.
We are told that force of friction acting on the block between A and B is 1.2 N and points A and B are 0.5 m apart. Thus;
Frictional Force; F_f = 1.2 N.
∴ Work done by friction; W_f = -F_f × d
W_f = -1.2 × 0.5
W_f = -0.6 J (negative sign because frictional force is force that is opposing motion)
Now, we are told that the kinetic energies of the block at A and B are 4.0 J and 5.6 J respectively.
Since the block was pushed from point A to point B, then we can say that;
Change in kinetic energy = total work done = 5.6 - 4
Total work done = 1.6 J
I earlier said that we have work done by friction and work done by the applied force acting on this system. Thus;
Total work done = Work done by friction + work done by force
Plugging in the relevant values gives us;
1.6 = -0.6 + work done by force
work done by force = 1.6 + 0.6
work done by force = 2.2 J
Read more at; https://brainly.com/question/13509648
