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Why is the unit of angular velocity sometimes rad / s and sometimes 1 / S?
Because the radian unit "rad" is the arc length corresponding to the angle divided by the radius, which is "@ = L / R", we can know that the unit of angle is "m / M", that is "1" (Yi), so the angle unit can also be omitted
1. Does the vehicle speed refer to the linear speed of the wheel edge or the speed of the wheel rotation center? 2. Is the angular speed a scalar or a vector?
The speed of a car is equal to the linear speed of the edge of the wheel relative to the car. The angular speed is a vector. The right hand rules the thumb direction
There is a 6cm long chord on the wheel with a diameter of 10cm, and P is the midpoint of the chord. If the wheel rotates at a speed of 5 radians per second, the arc length of point P after 5 seconds is 0______ cm．
As shown in the figure, connect OP and extend it to dot a, ∵ CD = 6cm, OD = 5cm ∵ OP = 4cm ∵ A and P have the same angular velocity. After 5 seconds, the rotation angle of point P is 25 radians, and the arc length of point P is 25 × 4 = 100 (CM). So the answer is: 100
The outside diameter of a bicycle wheel is 75 cm. If the average speed of a wheel is 100 laps per minute, how many minutes does it take to cross the 1413 meter road
75 * 3.14 = 235.5 (CM) (one circle)
235.5 * 100 = 23550 (CM) (one minute)
1413m=141300cm
141300 divided by 23550 = 6 (points)
The diameter of the car's wheels is 1.2m. If the speed of the wheels reaches 200 revolutions per minute, can you find out how many meters the car travels per hour?
200 * 60 per hour = 12000 cycles
The circumference of each circle is 3.14 * 1.2 = 3.768m
Speed 12000 * 3.768 = 45216 M = 45.216 km / h
When the car turns on a horizontal curve with radius r, the friction coefficient between the wheel and the ground is μ, then the maximum speed of the car is______ ．
According to Newton's second law, μ mg = mv2r, the maximum speed v = μ gr. so the answer is: μ gr
How to calculate slip of asynchronous motor?
S=(n0-n)/n0
N0 is the synchronous speed
N is the actual speed
n0=60f/p
How to calculate the slip of asynchronous motor?
The difference between synchronous speed and rotor speed of asynchronous motor is called slip, and the percentage value of the ratio of slip and synchronous speed is called slip rate of asynchronous motor
Slip of induction motor
One day, the rated speed of a 50 Hz induction motor in p162 of the third edition of electrical engineering is NN = 730r / min. try to find out the rated slip rate of the motor. In the answer, it is said that because the rated speed is lower than the synchronous speed, we know that the synchronous speed of the machine is 750 R / min, and the pole number is 2p = 8. I want to ask how the synchronous speed 750 and the pole number 2p = 8 come from?
Synchronous speed = 50 / P * 60. The rated speed is 730r / min, and it can not be confirmed that the synchronous speed is 750r / min or 900r / min (2P = 6). If the no-load speed is 730r / min, it can be basically determined that the synchronous speed is 750r / min
How to measure slip of asynchronous motor?
The slip of asynchronous motor is the ratio of the difference between the actual speed and the synchronous speed and the synchronous speed. The measurement of slip can be changed into the measurement of the actual speed and the synchronous speed
The actual speed is usually measured with a tachometer
The synchronous speed is directly proportional to the power supply frequency, and the synchronous speed = frequency * 60 / pole pairs of the motor. Therefore, it can be obtained by measuring the frequency of the power supply voltage or current
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