An object of mass m = 2.9 g and charge Q = +42 µC is attached to a string and placed in a uniform electric field that is inclined at an angle of 30.0° with the horizontal. The object is in static equilibrium when the string is horizontal.
a) Find the magnitude of the electric field. b) Find the tension in the string. i know A is -mg + sin 30 * qE =0 but i don't know how to solve for it

Respuesta :

(a) 
F= qE 

F sin 30.0° = mg 
= 0.0026(10) 
= 0.026 N 
F = 0.052 N 

E = F/q = 0.052 / 60µ = 867 N/C 

(b) 
T = F cos 30.0° 
= 0.0450 N

[tex]\frac{m\ g}{q \ sin \theta} [/tex]the equilibrium condition and the electric force we can find that the results are:

   a) Electric field E= 9.33 10² N/C

   b) String tension T = 3.39 109-2 N

Given parameters.

  • Body mass m= 2.9 g = 2.9 10-3 kg.
  • Electric charge of the body Q = 42 mC = 42 10-6 C.
  • The angle = 30º

To find.

    a) Electric field.

     b) String tension.

Equilibrium Condition.

Newton's second law gives a relationship between the net force, the mass and the acceleration of the body, in the case that the acceleration is zero it is called a condition of equilibrium.

        ∑ F = 0

A free body diagram is a diagram of the forces of the system without the details of the bodies, in the attachment we see a free body diagram of the system.

They indicate that the body is in an electric field, therefore the electric force is

            F = q E

Where q is the charge of the body E the electric field that is a vectorial magnitude.

Let us write the equilibrium condition for each axis.

y-axis

        Fe sin 30 -W = 0

        q E sin 30 = m g

         E = [tex]\frac{m \g }{q \ sin \theta } [/tex]

       

Let's calculate.

          E = [tex]\frac { 2.9 \ 10^{-3} \ 9.8 }{42 \ 10^{-6} \ sin30 } [/tex]

          E = 9.33 10² N/C

x-axis

         Fe cos 30 – T = 0

         T = qE cos 30

Let's calculate.

         T = 42 10-6 9.33 10² cos 30

         T = 3.39 10-2N

In conclusion using the equilibrium condition and the electric force we can find that the results are:

   a) Electric field E= 9.33 10² N/C

   b) String tension T = 3.39 10³ N

Learn more about the equilibrium condition here:  brainly.com/question/24742518

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