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creativ13 [48]
3 years ago
14

The lanthanides are all radioactive true or false

Physics
1 answer:
Oksi-84 [34.3K]3 years ago
3 0

Answer:

False

Explanation:

All the lanthanides are not radioactive in nature. Just one of the lanthanides are radioactive.

  • The lanthanides belong to the f-block on the periodic table
  • Only Promethium in this group are radioactive in nature.
  • Other elements in the lanthanide series might have radioactive isotopes.
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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
A 6 N and a 10 N force act on an object. The moment arm of the 6 N force is 0.2 m. If the 10 N force produces five times the tor
Levart [38]

Answer:

The moment arm is 0.6 m

Explanation:

Given that,

First force F_{1}=6\ N

Second force F_{2}=10\ N

Distance r = 0.2 m

We need to calculate the moment arm

Using formula of torque

\tau=Force\times lever\ arm

So, Here,

\tau_{2}=5 \tau_{1}

We know that,

The torque is the product of the force and distance.

Put the value of torque in the equation

F_{2}\times d_{2}=5\times F_{1}\times r_{1}

r_{2}=\dfrac{5\times F_{1}\times r_{1}}{F_{2}}

Where, F_{1}=First force

F_{1}=First force

F_{2}=Second force

r_{1}= distance

Put the value into the formula

r_{2}=\dfrac{5\times6\times0.2}{10}

r_{2}=0.6\ m

Hence, The moment arm is 0.6 m

6 0
3 years ago
The world’s longest organ pipe, in the boardwalk hall auditorium in atlantic city, is 64 feet long. what is the fundamental freq
zepelin [54]

The fundamental frequency of this open-open pipe is 8.82 Hz

The quantity of waves that pass a set location in a predetermined period of time is known as frequency. Frequency is the number of full cycles per second in the alternating current direction for an oscillating or fluctuating current. The hertz, also known as Hz, is the accepted unit of frequency.

The temporal rate of change observed in oscillatory and periodic phenomena, such as mechanical vibrations, audio signals (sound), radio waves, and light, is specified by the frequency, an essential parameter in science and engineering.

Assume vs = 344 m/s

f1 = vs/2L

   = 344 m/s/ 2∙64 ft/(3.281 ft/m)

   = 8.82 Hz

To know more about Frequency refer:

brainly.com/question/14131991

#SPJ4

5 0
2 years ago
A 1430 kg car speeds up from 7.50 m/s to 11.0 m/s in 9.30 s. Ignoring friction, how much power did that require?(unit=W)PLEASE H
Aleks04 [339]

Answer:

Kinetic energy = (1/2) (mass) (speed²)

Original KE = (1/2) (1430 kg) (7.5 m/s)²  =  40,218.75 joules

Final KE  =  (1/2) (1430 kg) (11.0 m/s)²  =   86,515 joules

Work done during the acceleration = (40218.75 - 86515) = 46,296.25 joules

Power = work/time = 46,296.25 joules / 9.3 sec  =  4,978.1 watts .

Explanation:

Dont report my answer please

3 0
3 years ago
A motorist enters a freeway at 45 km/h and accelerates uniformly to 99 km/h. From the odometer in the car, the motorist knows th
Marat540 [252]

Answer:

a)  19440 km/h²

b) 10 sec

Explanation:

v₀ = initial velocity of the car = 45 km/h

v = final velocity achieved by the car = 99 km/h

d = distance traveled by the car while accelerating = 0.2 km

a = acceleration of the car

Using the kinematics equation

v² = v₀² + 2 a d

99² = 45² + 2 a (0.2)

a = 19440 km/h²

b)

t = time required to reach the final velocity

Using the kinematics equation

v = v₀ + a t

99 = 45 + (19440) t

t = 0.00278 h

t = 0.00278 x 3600 sec

t = 10 sec

5 0
3 years ago
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