Page 25 of physics, when the car is not at the highest point of the arch bridge or the lowest point of the concave bridge, can we use the appeal method to solve it If the car is not at the highest point of the arch bridge or the lowest point of the concave bridge, it can be solved by the appeal method On page 25 of the physics book, is the centripetal force on the middle and both sides of the bridge the same when the car crosses the bridge? When the speed is at the highest point, it can't exceed a certain limit. That is, the speed is different, and the center of gravity on both sides of the bridge is different. So is the centripetal force the same?

You can't

12-4 (3x-1) > or = 2 (2x-16)

12 - 4(3x-1) >= 2(2x-16) => 12 - 12x + 4 >= 4x - 32 => 16x x

A. B is 490 km away from the two places. A and B start from the two places and run in opposite directions. If they start at the same time, they will meet in 7 hours. If a drives for 7 hours, B will start again

If we set out at the same time, we will meet in 7 hours, and the sum of speed of Party A and Party B is 490 / 7 = 70 km
If a drives for 7 hours and B starts again, and the result is that two cars meet after 2 hours, then the speed of a car is (490-70 * 2) / 7 = 50 km
B's speed is 70-50 = 20 km

Use the square difference formula to calculate: (1-1 / 4) (1-1 / 9) (1-1 / 2001 ^ 2) (1-1 / 2002 ^ 2) please

The original formula = (1 + 1 / 2) (1-1 / 2) (1 + 1 / 3) (1-1 / 3); (1 + 1 / 2002) (1-1 / 2002) = (1 / 2) (2003 / 2002) = 2003 / 4004 = (3 / 2) (1 / 2) (4 / 3) (2 / 3)... (2003 / 2002) (2001 / 2002)

I'm talking about brain twists. The square of a thousand is equal to the multiplication of three hundred

Do everything possible

A batch of fruit, apple is 56 of pear, pear is 23 of banana. Apple 150 kg, banana how many kg?

150 △ 56 △ 23 = 150 × 65 × 32 = 270 kg; answer: banana has 270 kg

Given 10A = 2, 10b = 3, find the value of 103a + 2B

So the value of 103a + 2b is 72

Let Z be an imaginary number, w = Z + (1 / z) be a real number, and - 1
u=(1-Z)/(1+Z)

Let z = x + Yi, then w = Z + 1 / z = x + Yi + (x-yi) / √ (X & # 178; + Y & # 178;) = [x + X / √ (X & # 178; + Y & # 178;)] + [Y-Y / √ (X & # 178; + Y & # 178;)] i
Because W is a real number and - 1

The fruit shop brought in 25 baskets of apples and 60 baskets of pears, weighing 2645 kg
The fruit shop shipped 25 baskets of apples and 60 baskets of pears, weighing 2645 kg. It is known that each basket of apples is 20 kg lighter than each basket of pears. How many kg are the average weight of each basket of pears and apples?
solve equations:
8.7（36.6-x）=0
Solving practical problems with equations

Suppose the apple weighs x kg and the pear weighs x + 20 kg
25X+60(X+20)=2645
25X+60X+1200=2645
85X =1445
X = 17 apples: 17 kg
Pear: 17 + 20 = 37kg

Take any 27 natural numbers from 1 to 50, and the sum of two numbers must be equal to 52. Please list the formula and explain the reason

If the sum of two numbers obtained is not 52, group 50 numbers, and the sum of two numbers in each group is 52 (50,2) (49,3) (48,4) (47,5) (46,6) （28,24）（27,25）
26 and 1 do not need the sum of any number in the required range is not 52. If you want the sum of two numbers to be not 52 separately, you can only take one number in each group. There are 50-27 + 1 = 24 groups. If you take 26 and 1 again, the sum of two numbers will not be 52
When the 27th number is taken, it must be added to a number in group 24 to be 52, so take any 27 natural numbers from 1 to 50, and the sum of 2 numbers must be equal to 52