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2 years ago

Does a generator start a Direct Current?

1 answer:

3 0

A direct-current (DC) generator is a rotating machine that supplies an electrical output with unidirectional voltage and current. ... The field is produced by direct current in field coils or by permanent magnets on the stator. The output, or armature, windings are placed in slots in the cylindrical iron rotor.

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As a quality test of ball bearings, you drop bearings (small metal balls), with zero initial velocity, from a height of 1.94 m i

11Alexandr11 [23.1K]

Answer:

The average acceleration of the bearings is $0.77\times10^{3}\ m/s^2$

Explanation:

Given that,

Height = 1.94 m

Bounced height = 1.48 m

Time interval $t=14.86\times10^{-3}\ s$

Velocity of the ball bearing just before hitting the steel plate

We need to calculate the velocity

Using conservation of energy

$mgh=\dfrac{1}{2}mv^2$

Put the value into the formula

$9.8\times1.94=\dfrac{1}{2}\times v^2$

$v=\sqrt{2\times9.8\times1.94}$

$v=6.166\ m/s$

Negative as it is directed downwards

After bounce back,

We need to calculate the velocity

Using conservation of energy

$mgh=\dfrac{1}{2}mv^2'$

Put the value into the formula

$9.8\times1.48=\dfrac{1}{2}\times v^2'$

$v'=\sqrt{2\times9.8\times1.48}$

$v'=5.38\ m/s$

We need to calculate the average acceleration of the bearings while they are in contact with the plate

Using formula of acceleration

$a=\dfrac{v-v'}{t}$

Put the value into the formula

$a=\dfrac{5.38-(-6.166)}{14.86\times10^{-3}}$

$a=776.98\ m/s^2$

$a=0.77\times10^{3}\ m/s^2$

Hence,The average acceleration of the bearings is $0.77\times10^{3}\ m/s^2$

6 0

2 years ago

A boy throws a ball up into the air with a speed of 8.2 m/s. The ball has a mass of 0.3 kg. How much gravitational potential ene

diamong [38]

We can use the law of conservation of energy to solve the problem.

The total mechanical energy of the system at any moment of the motion is:
$E=U+K = mgh + \frac{1}{2}mv^2$
where U is the potential energy and K the kinetic energy.

At the beginning of the motion, the ball starts from the ground so its altitude is h=0 and therefore its potential energy U is zero. So, the mechanical energy is just kinetic energy:
$E_i = K_i = \frac{1}{2}mv^2 = \frac{1}{2}(0.3 kg)(8.2 m/s)^2=10.09 J$

When the ball reaches the maximum altitude of its flight, it starts to go down again, so its speed at that moment is zero: v=0. So, its kinetic energy at the top is zero. So the total mechanical energy is just potential energy:
$E_f = U_f$
But the mechanical energy must be conserved, Ef=Ei, so we have
$U_f = K_i$
and so, the potential energy at the top of the flight is
$U_f = K_i = 10.09 J$

7 0

2 years ago

Read 2 more answers

Describe how a metamorphic rock might become a sedimentary rock over time.

andriy [413]

<span>Metamorphic rock undergoes weathering, erosion; the particles are deposited and undergo lithification.</span>

7 0

2 years ago

Which measurements are equal to 321 decimeters? Check all that apply.

S_A_V [24]

32,100 Millimeters
3,210 Centimeters
3.21 Decameters

Hope It Helps

5 0