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vaieri [72.5K]
4 years ago
12

A force is always required to move an object from rest

Physics
1 answer:
denis-greek [22]4 years ago
6 0
  <span> True a resultant force is needed </span>
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An AC generator consists of 20 circular loops of wire with an area of 75 cm2. It has a maximum induced voltage of 24 V. If its a
Monica [59]

Faraday's law allows us to find the magnetic field that produces the emf in the rotating system is:

  • The magnetic field is:  B = 0.424 T

Faraday's law of induction states that when the magnetic flux changes in time, an induced electromotive force is produced.

            fem = - \frac{d \Phi_B }{dt}  

where fem is the induced electromotive force and Ф the flux,

The magnetic flux is the scalar product of the field and the area.

           \Phi_B = B . A = B A  \ cos \theta  

In this case we have several turns, so the expression remains.

           fem = - N B A \ \frac{d cos \theta}{dt}  

Indicate that the turns rotate at a constant frequency, therefore we can use the uniform rotational motion ratio.

           

           θ = w t

We substitute

 

         fem = - N B A \ \frac{d \ cos \ wt}{dt}\\fem =  N B A w sin \ wt

the maximum induced electromotive force occurs when the sine function is ±1

          fem = N B A w

They indicate that the fem = 24 V, the number of the turn is N = 20, the area is A = 75 cm² = 75 10⁻⁴ m² and the frequency f = 60 Hz

Frequency and angular velocity are related.

           w = 2π f

We substitute.

           fem = N B A 2π f

           B = \frac{fem }{2 \pi \ NA \ f}  

Let's calculate.

         B= \frac{24 }{2\pi \ 20 \ 75 \ 10^{-4} 60}B = 24 / 2pi 20 75 10-4 60

         B = 0.424 T

In conclusion, using Faraday's law we can find the magnetic field that produces the emf in the rotating system is:

  • The magnetic field is; B = 0.424 T

Learn more about Faraday's law here:  brainly.com/question/24617581

8 0
3 years ago
A record of travel along a straight path is as follows: 1. Start from rest with constant acceleration of 2.65 m/s2 for 17.0 s. 2
nlexa [21]
Hello

Let's solve the problem in the three different steps

1) Uniformly accelerated motion, with acceleration a_1 = 2.65~m/s^2 and for a total time of t_1=17~s. The body is initially at rest, so the distance covered is given by
S= \frac{1}{2}a_1t_1^2=382.9~m
Calling v_f and v_i the final and initial velocity, and since the v_i=0~m/s because the body starts from rest, we can use
a= \frac{v_f-v_i}{t}
to find the final velocity after this first leg:
v_{f}=v_i+a_1t_1=45~m/s
And the average velocity in this first leg is
v_1= \frac{v_f+v_i}{2}=22.5~m/s

2) Uniform motion. The velocity is constant and it is equal to the final velocity of the first leg: v_2=45~m/s. This is also the average velocity of the second leg. 
The total time of this second leg is t_2=1.60~min = 96~s. The distance covered is given by
S_2=v_2t_2=45~m/s \cdot 96~s=4320~m

3) Uniformly decelerated motion, with constant deceleration of a_3=-9.39~m/s^2 and for a total time of t_3=4.8~s. Here, the initial velocity of the body is the final velocity of the previous leg, i.e. v_i=45~m/s. Therefore, the distance covered in this leg is given by
S_3=v_i t_3 + \frac{1}{2} a_3 t^2 =107.8~m
The final velocity in this leg is given by
v_f=v_i+at=45~m/s-9.39~m/s^2 \cdot 4.8~s = -0.07~m/s
The negative sign means that after decelerating, the body has started to go in the opposite direction. Similarly to step 1, the average velocity in this leg is given by
v_3 =  \frac{1}{2}(v_f+v_i)=  \frac{1}{2}(-0.07~m/s+45~m/s)=  22.5~m/s

4) Finally, the total distance covered in the motion is
S=S_1+S_2+S_3=382.9~m+4320~m+107.8~m=4810.7~m
To find the average velocity, we must "weigh" the average velocity of each leg for the correspondent time of that leg:
v_{ave}= \frac{v_1t_1+v_2t_2+v_3t_3}{t_1+t_2+t_3}=40.8~m/s
8 0
3 years ago
hey pls help with this HDJSJDH im rlly bad at this kinda stuff :,) i'll mark the correct answer brainliest
timama [110]
I am pretty sure it’s A
The cue exerts force onto the white ball which pushes the blue ball into the direction of the hole.
7 0
3 years ago
Read 2 more answers
If the mass of an object increases, the force acting on it, such as gravitational force, also increases
strojnjashka [21]
Its true because I just took the the test and it was right
I hope i helped you got it right
4 0
4 years ago
А
timurjin [86]

Answer:

i hope it will be useful for you

Explanation:

F=5.6×10^-10N

R=93cm=0.93m

let take m1 and m2 =m²

according to newton's law of universal gravitation

F=m1m2/r²

F=m²/r²

now we have to find masses

F×r²=m²

5.6×10^10N×0.93m=m²

5.208×10^-9=m²

taking square root on b.s

√5.208×10^-9=√m²

so the two masses are m1=7.2×10^-5

and m2=7.2×10^-5

8 0
4 years ago
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