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:
Time = 40 s
It will take the spaceship 40s to coast that distance.
Explanation:
Using the impulse momentum equation;
Impulse = change in momentum
Ft = m(∆v) ........1
Given;
Force F = 1200kN
time of action t = 20s
Mass of spaceship m = 8.0×10^4 kg
∆v = change in velocity
Substituting the values into equation 1;
1200kN × 20s =8.0×10^4 kg × ∆v
∆v = 1200000×20/80000
∆v = 300 m/s
Since it was initially at rest, V0 = 0
Final velocity V2 = 300 + 0
V2 = 300m/s
Time To travel 12 km,
Time = distance/speed
Distance = 12 km = 12000m
Speed = 300m/s
Time = 12000/300
Time = 40 s
It will take the spaceship 40s to coast that distance.
Answer:
The answer is 35.45 yds
Explanation:
You have to picture this to be able to understand it better (see attachment).
Start at the origin which is when the quarterback (QB) takes the ball. He runs backwards 12.1 yards, runs sideways for 19.8 yards (it doesn´t matter if he runs right or left), then he throws the ball forward 41.5 yards. If you look at the attachment, you can see I drew the path that the football followed. And then connected the dots from the origin and finish. The distance between those two points is the magnitude of the resultant displacement.
In order to calculate it, all you need to do is use the Pythagoream theorem, which says that the square of the hypotenuse equals the sum of the squares of the legs a and b of the triangle rectangle.
then solve for R
In this case, you know the length of leg a to be 19.8 yards which how much it moves sideways. And then, to get the length of leg b, all you need to do is substract how much it moved backwards from the 41.5yards forward displacement. This results in b leg being 29.4 yards long.
Now you have a triangle with:
- a = 19.8 yards
- b = 29.4 yards
Substituting this numbers in the equation:
- R = 35.45 yards
Answer: Contact force
a. Applying break in a vehicle.
d. The speed of ball rolling on ground is reduced
Non contact force
b. A coconut falling from a coconut tree.
c. The planets revolving around the sun.
Explanation:
The contact force is the force which exerts when one object or entity comes in contact with other object or entity. For example, on application of break the vehicle stops, the force is applied on the breaks to stop the vehicle. The ball rolling on the ground the speed reduces so the application of force on the ground also reduces.
The non contact force is the force one object exerts on the other without coming in direct contact with the other object. The force exerted by one object on other due to gravity is a non contact force. The coconut falling on the ground and planets revolving around the sun are examples of non contact force due to gravity.
b.the covalent circuit is held throw magnetic waves
