（ab+1）2-（ab-1）2．

（ab+1）2-（ab-1）2．

（ab+1）2-（ab-1）2，=（ab+1+ab-1）-（ab+1-ab+1），=2ab•2，=4ab．

What is (AB) quadratic

(AB) quadratic
=A quadratic times b quadratic

If | A-4 + + (B + 2) square, then a of B is equal to the answer of | T-T,

It should be | A-4 | + (B + 2) square = 0
If one is greater than 0, the other is less than 0
So both are equal to zero
So A-4 = 0, B + 2 = 0
a=4,b=-2
Power a of B = (- 2) to the fourth power = 16

When the speed is very high, the resistance is proportional to the square of the speed
In the process of high-speed and uniform motion of aircraft and train, if this is to increase their uniform motion speed to twice the original speed, the output power of the engine,
A doubled
B increased by 4 times
C increased by 6 times
D increased by 8 times

The resistance is proportional to the square of the velocity
That is, f = kV ^ 2
Traction = resistance, i.e. f = f
P=Fv=kv^3
If this is to double the speed of their uniform motion
Then f '= K (2V) ^ 2 = 4KV ^ 2
F'=f'
P'=F'(2V)=8kv^3
So the output power of the engine, D, increases 8 times

Let the resistance of the aircraft in flight be proportional to the square of the speed. If the actual power of the engine is p when the aircraft is flying at a constant speed of V, then the actual power of the engine is p when the aircraft is flying at a constant speed of 2V______ P．

Let f = Kv2 be the resistance of the aircraft in flight. When the aircraft is flying at constant speed, the resistance of the aircraft is equal to the traction of the aircraft. Therefore, when the aircraft is flying at speed V, P = FV = Kv2 · v = Kv3. When the aircraft is flying at constant speed 2V, P ′ = f ′ V ′ = K (2V) 3 = 8p, so the answer is: 8

When the aircraft is flying, the air resistance is proportional to the square of the velocity
When the power of the engine is p, the power of the engine is

Mathematically speaking, it may be n * n * n * P, but if it's a jet, first of all, the jet doesn't talk about power, but thrust. Then, in order to keep the lift equal to the gravity constant, it's not so simple to reduce the angle of attack when the speed increases

Let the air resistance of an aircraft in flight be proportional to the square of its velocity. When the aircraft is flying at constant velocity V, the power of the engine is p. if the aircraft is flying at constant velocity 3V, the power of the engine is ()
A. 3PB. 9PC. 18PD. 27P

When the aircraft is flying at a constant speed, the traction force is equal to the resistance, that is, f = f ′ = Kv2, then the engine power is p = FV = Kv3, that is, the engine power is proportional to the third power of the speed. Therefore, when the speed of the aircraft becomes three times, the engine power becomes 27 times, so option D is positive So D

Suppose that the resistance of an aircraft in flight is proportional to the square of its velocity. When the aircraft flies at a constant velocity V, the engine work of the aircraft will increase
If the mass of the aircraft is m and the engine power is increased to 2p, how much acceleration does the aircraft begin to accelerate?

At the beginning of flying with V, the power is p, so the traction force is f = P / V, and the uniform traction force is equal to the resistance force F = F
When the power transiently changes to 2p, the traction force changes to 2F, the speed does not change, and the resistance is still f = P / v
So the external force is f = 2f-f = 2P / V-P / v = P / V, so the acceleration is a = f / M = P / VM

The power of the engine is p when the aircraft is flying at a constant speed V, if the air resistance of the aircraft is proportional to the square of the flight speed
Then, when the engine power is increased to 4P, the aircraft's uniform speed will increase to?

When the aircraft flies at a constant speed, the traction force is equal to the resistance, and the resistance f is equal to kV ^ 2
fv=P,P=kv^3
4P=fV=kV^3
V^3=4v^3
The third root of V ^ = V * 4

Why is bracket 4: when a paper cone of the same shape falls, the air resistance is proportional to the square of the speed
29. (4 points) in the comprehensive practical activities, students of an interest group used paper cones and small metal balls to study the relationship between air resistance and speed. Three identical paper cones were selected, each with a mass of M and numbered as a, B and c. a small metal ball with a mass of 3M was fixed in paper cone B, Small metal balls with a mass of 8 m are fixed in the C paper cone. Let them fall freely from different heights, and take the vertical brick wall as the background. When entering the area of the vertical brick wall, use the camera to record the movement process of the paper cone by exposing it every equal time, as shown in the figure. Please answer the following questions according to the figure:
(1) The following statement is correct for the motion process in the figure
A. Only a moves in a straight line at a constant speed
B. It's just a uniform straight line
C. Only C moves in a straight line at a constant speed
D. A, B, C do uniform linear motion
(2) For the motion process in the figure, the ratio of the velocities of the three paper cones a, B and C is, and the ratio of the air resistance they are subjected to is. The experimental conclusion drawn from this is
29.(l)D
(2) 1: 2: 3; 1: 4: 9 paper cone of the same shape, the air resistance when falling is proportional to the square of velocity
(1) The title says: use the camera to record the movement process of the paper cone by exposing it once every other equal time, so the time between two adjacent images of the same paper cone is the same, and the distance through the image is also the same, so a, B, C three paper cones do uniform linear motion
(2) The distance between the three paper cones a, B and C is different, that is, the distance in the same time is different. The distance ratio is 1:2:3, so the speed ratio is 1:2:3
(3) Because the paper cones a, B and C all move in a straight line at a uniform speed, the total gravity and air resistance are equal forces for the same paper cone. The total gravity of a is mg; the total gravity of B is 4mg; the total gravity of C is 9mg, The air resistance of a, B and C is mg, 4mg and 9mg respectively. The ratio of air resistance of a, B and C is 1:4:9
(4) From (2) (3) above, it can be concluded that the air resistance of the paper cone with the same shape is proportional to the square of the velocity

Since the three paper cones are moving in a straight line at a constant speed in the process of measurement, it shows that their forces are balanced, that is to say, the air resistance is equal to their respective weight, and the ratio of their weight is: 1m: 4m: 9m, so it can not be completely concluded that the air resistance is directly proportional to the square of the speed