One degree kelvin equals one degree Fahrenheit ? True or false

A _____ is used in a motor to switch the direction of the magnetic field created by the current.

insens350 [35]

Answer:

A _commutator_ is used in a motor to switch the direction of the magnetic field created by the current.

The rotating part of a motor that holds the electromagnets is called the __armature___.

Electric current passes through the _brushes_ and into the electromagnets in an electric motor.

A motor turns _electrical_ energy into _mechanical_ energy.

Explanation:

A commutator, which is a split ring rotary switching device, reverses the direction of the current between the external circuit and the rotor. Reversing the current reverses the magnetic field.

The armature comprises the rotating part of the motor and the electromagnets

A brush is the electrical contact for conducting current through the moving and stationary parts of an electric motor

An electric motor turns electrical energy into mechanical energy.

8 0

3 years ago

Why did boy (the observer) hear the pitch of the sound change? What does this tell us about the frequency of the sound? Support

timofeeve [1]

Answer:

<u>because of the doppler effect</u>

Explanation:

<em>Remember</em>, the doppler effect refers to the changes in sound (frequency of sound) observed by a person who is in a position relative to the wave source.

In this example, we notice as the train comes closer to the boy, the sound becomes louder also increasing the pitch slightly, the doppler effect sets in when the train passes the boy because the boy notices a decrease in the pitch of the moving train.

We learn from the change in the observed sound of the train that the frequency of the sound is determined by the distance of the observer from the wave source.

In other words, the closer the source of the sound to the observer; the faster it travels to the observer, however, the farther it is; the lesser it is; the greater the sound heard.

5 0

2 years ago

A small block of mass 20.0 grams is moving to the right on a horizontal frictionless surface with a speed of 0.68 m/s. The block

Usimov [2.4K]

Answer:

a) $v'=-0.227\ m.s^{-1}$

b) $v=1.36\ m.s^{-1}$

Explanation:

Given:

mass of the lighter block, $m'=0.02\kg$

velocity of the lighter block, $u'=0.68\ m.s^{-1}$

mass of the heavier block, $m=0.04\ kg$

velocity of the heavier block, $u=0\ m.s^{-1}$

a)

Using conservation of linear momentum:

$m'.u'+m.u=m'.v'+m.v$

where:

$v'=$ final velocity of the lighter block

$v=$ final velocity of the heavier block

$m'.u'=m'.v'+m.v$

$m'(u'-v')=m.v$ ........................(1)

Since kinetic energy is conserved in elastic collision:

$\frac{1}{2}m'.u'^2=\frac{1}{2}m'.v'^2+\frac{1}{2}m.v^2$

$m'(u'^2-v'^2)=m.v^2$

$m'(u'-v')(u'+v')= m.v^2$

divide the above equation by eq. (1)

$v=u'+v'$ .............................(2)

now we substitute the value of v from eq. (2) in eq. (1)

$m'(u'-v')=m(u'+v')$

$\frac{m'+m}{m'-m} =\frac{u'}{v'}$

$\frac{0.02+0.04}{0.02-0.04} =\frac{0.68}{v'}$

$v'=-0.227\ m.s^{-1}$ (negative sign denotes that the direction is towards left)

b)

now we substitute the value of v' from eq. (2) in eq. (1)

$m'(u'-v+u')=m.v$

$2m'.u'=(m-m')v$

$2\times 0.02\times 0.68=(0.04-0.02)\times v$

$v=1.36\ m.s^{-1}$

6 0

2 years ago

These nerve cells are needed in muscle and tendons to detect degree of stress and stretching as a sensory activity. A. Ganglia.

SOVA2 [1]

Answer:

D.Proprioceptors

Explanation:

"Proprioceptors is Sensory receptors found in muscle an tendons that detect their degree of stretch"

4 0

2 years ago

As SCUBA divers go deeper underwater, the pressure from the weight of all the water above them increases tremendously which comp

slavikrds [6]

Answer: A.

As a diver rises, the pressure on their body decreases which allows the volume of the gas to decrease.

Explanation:

The problem is that a diver, experiences an increased pressure of water compresses nitrogen and more of it dissolves into the body. Just as there is a natural nitrogen saturation point at the surface, there are saturation points under water. Those depend on the depth, the type of body tissue involved, and also how long a diver is exposed to the extra pressure. The deeper a diver go, the more nitrogen the body absorbs.

The problem is getting rid of the nitrogen once you ascend again. As the pressure diminishes, nitrogen starts dissolving out of the tissues of the diver's body, a process called "off-gassing." That results in tiny nitrogen bubbles that then get carried to the lungs and breathed out. However, if there is too much nitrogen and/or it is released too quickly, small bubbles can combine to form larger bubbles, and those can do damage to the body, anything from minor discomforts all the way to major problems and even death.

4 0

2 years ago