This is fairly easy. The earlier view of the solar system (geocentric) was all based on how other planets and the sun were constantly revolving the earth and we were completely stationary. The Heliocentric view has been proved to be accurate, and it is that the sun is stationary and the planets are revolving it. The similarities are that in that time, it was a continued belief that the planets were the Roman Gods, i.e. Jupiter, Neptune. Another thing is that they were correct in the Geocentric theory with the thought that the planets revolved around something.
INDUCTION MOTOR:-
Speed:-Less speed range than PMAC motors • Speed range is a function of the drive being used — to 1,000:1 with an encoder, 120:1 under field-oriented control
Reliability:-Waste heat is capable of degrading insulation essential to motor operation • Years of service common with proper operation
Power density:-Induction produced by squirrel cage rotor inherently limits power density
Accuracy:-Flux vector and field-oriented control allows for some of accuracy of servos
Cost:-Relatively modest initial cost; higher operating costs
PERMANENT MAGNET MORTOR:-
speed:-VFD-driven PMAC motors can be used in nearly all induction-motor and some servo applications • Typical servomotor application speed — to 10,000 rpm — is out of PMAC motor range
Reliability:-Lower operating temperatures reduces wear and tear, maintenance • Extends bearing and insulation life • Robust construction for years of trouble-free operation in harsh environments.
power density:-Rare-earth permanent magnets produce more flux (and resultant torque) for their physical size than induction types.
Accuracy:-Without feedback, can be difficult to locate and position to the pinpoint accuracy of servomotors
<span>Cost:-Exhibit higher efficiency, so their energy use is smaller and full return on their initial purchase cost is realized more quickly</span>
Answer:
57 kg
Explanation:
Mass of seesaw = 20 kg
Length of seesaw = 4 m
Mass of child on the longer end = 30 kg
The weight of the seesaw acts at the center i.e. 2m
The algebraic sum of moments of all forces about any point is zero, hence, using the fulcrum as the reference point:
[x * 9.8* 1.5] - [20 * 9.8* (2.5 - 2)] - [30 * 9.8 * 2.5] = 0
=> 14.7x = (20*9.8*0.5) + 735
14.7x = 98 + 735
14.7x = 833
=> x = 833/14.7
x = 57 kg
Answer:
Explanation:
Let assume that gases inside bulbs behave as an ideal gas and have the same temperature. Then, conditions of gases before and after valve opened are now modelled:
Bulb A (2 L, 2 atm) - Before opening:
Bulb B (3 L, 4 atm) - Before opening:
Bulbs A & B (5 L) - After opening:
After some algebraic manipulation, a formula for final pressure is derived:
And final pressure is obtained:
