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4 years ago

Why is the question correct

Physics

1 answer:

inysia [295]4 years ago

3 0

Answer:

Sometimes the correct answer is there, as is, but the test has a different answer. Tell the teacher that the computer had the wrong answer.

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A motor with a brush-and-commutator arrangement has a circular coil with radius 2.5cm and 150 turns of wire. The magnetic field

Amanda [17]

Answer:

(a) 0.81 V

(b) 0.52 V

Explanation:

Number of turns, N = 150

Radius, r = 2.5 cm = 0.025 m

Magnetic field, B = 0.060 T

f = 440 rev/min = 440 / 60 = 7.33 rps

The maximum emf is given by

e = N x B x A x 2 x π x f

e = 150 x 0.060 x 3.14 x 0.025 x 0.025 x 2 x 3.14 x 7.33

e = 0.81 V

The back emf is given by

e' = 2e / π = 2 x 0.81 / 3.14 = 0.52 V

3 0

3 years ago

Validity of an experiment is based upon

igor_vitrenko [27]

Validity concludes the whole experimental values and concepts which makes that whether the results which are obtained meet all of the requirements of the scientific research method.

On which factors the validity of an experiment depends?

There are five components which are used in experiment: observations, questions, hypothesis, methods and results. The scientific method procedure is not only ensures that the same experiment can be repeated by other researchers, but this experiment is accepted. For example, there must have been arrange in a random way of the sample groups and proper work and care shows and the experiment is succeed.

So we can conclude that: Validity concludes the whole experimental values and concepts which makes that whether the results which are obtained meet all of the requirements of the scientific research method.

Learn more about Validity: brainly.com/question/25303029

SPJ1

4 0

2 years ago

What’s the weight of a box w/ a mass of 150kg on earth?

Orlov [11]

$\text{Weight ,} W = mg = 150 \times 9.8 =1470N$

8 0

2 years ago

Read 2 more answers

What is the equivalent resistance of a circuit that contains four 75.02

viktelen [127]

Answer:

option A is the correct answer

3 0

2 years ago

A 500 kg dragster accelerates from rest to a final speed of 100 m/s in 400 m (about a quarter of a mile) and encounters an avera

Fantom [35]

In order to accelerate the dragster at a speed $v_f = 100 m/s$ , its engine must do a work equal to the increase in kinetic energy of the dragster. Since it starts from rest, the initial kinetic energy is zero, so the work done by the engine to accelerate the dragster to 100 m/s is
$W= K_f - K_i = K_f = \frac{1}{2}mv_f^2=2.5 \cdot 10^6 J$

however, we must take into account also the fact that there is a frictional force doing work against the dragster, and the work done by the frictional force is:
$W_f = F_f d = -(1200 N)(400 m)= -4.8 \cdot 10^5 J$
and the sign is negative because the frictional force acts against the direction of motion of the dragster.

This means that the total work done by the dragster engine is equal to the work done to accelerate the dragster plus the energy lost because of the frictional force, which is $-W_f$ :
$W_t = W + (-W_f)=2.5 \cdot 10^6 J+4.8 \cdot 10^5 J=2.98 \cdot 10^6 J$

So, the power delivered by the engine is the total work divided by the time, t=7.30 s:
$P= \frac{W}{t}= \frac{2.98 \cdot 10^6 J}{7.30 s}=4.08 \cdot 10^6 W$

And since 1 horsepower is equal to 746 W, we can rewrite the power as
$P=4.08 \cdot 10^6 W \cdot \frac{1 hp}{746 W} =547 hp$

3 0

4 years ago

Read 2 more answers