As shown in the figure, the pressure of this streamlined car on the horizontal ground at high speed______ (select "increase", "decrease" or "unchanged"). The reason is______ ．

As shown in the figure, the pressure of this streamlined car on the horizontal ground at high speed______ (select "increase", "decrease" or "unchanged"). The reason is______ ．

As shown in the figure, the shape of the car is streamlined. When the car is running at high speed, the distance of the air passing through the upper part is longer than that under the lower part at the same time, with large flow velocity and low pressure. The car generates upward lift under the pressure difference, and the pressure of the car on the road is reduced, which is less than the gravity of the car, The air velocity under the car body is low and the pressure is high

When the car is running fast, which is the greater pressure on the ground than the gravity?

If the road surface is flat, it will be the same
If the road surface is convex, the pressure and gravity will increase

As shown in the figure, the gravity on the car is g, and the supporting force on the ground is f when the car is driving on a straight highway at a speed of 90km / h. If the influence of the surrounding air on it is considered, the following relationship between G and F is correct ()
A. G > FB. G = FC. G < FD

The air with equal mass passes through the upper and lower surfaces of the car at the same time. Because the upper surface of the car is curved and the lower surface is flat, when the car runs fast on a straight road, the air passing through the upper surface of the car has a high velocity and a low pressure; the air passing under the car has a low velocity and a high pressure, so the car receives an upward lift The pressure of the car on the ground (i.e. the supporting force F of the car on the ground) is less than the gravity of the car

Which is the greater pressure on the ground when a car is running at high speed on a water bottle road than when it is stationary?

Macroscopically speaking, high speed driving does not affect the force on the horizontal plane, so the pressure is the same
Not macroscopically speaking, the aerodynamics of the car determines that the high-speed car has a force similar to the aircraft take-off, which will reduce the downforce. This is also the reason why the car floats after high-speed driving

What are the symbols of gravity, pressure, support and friction?
Just these forces (the second stage of junior high school)? It seems that the sign of gravity is g?
Is it OK to use f or n for support?

Gravity n, pressure is f, pressure (the word "pressure" is a corner mark), supporting force can be n or F (in fact, if f is added with a corner mark, everything can be expressed), buoyancy is f, and friction force is f

What are the symbols for tension, pressure, support, and friction
It's like the sign of gravity is g

There are no specific symbols for the above forces, but there are commonly used symbols: tensile force is represented by T, pressure and supporting force are represented by FN, and friction force is represented by F

Symbols of gravity, friction and elasticity

Gravity: G
Friction: F
Elasticity: F

Resistance, friction, pull, thrust, gravity symbol science junior high school 1 year J used all

G in Newtonian mechanics of gravity, W, P, Q in analytical mechanics
F (F is the subscript) or F is used to analyze P, Q in resistance Newtonian mechanics
The friction is the same as above
Tension f or C P, Q in analytical mechanics
P, Q in thrust f analytical mechanics

Resistance is the weight of the car, gravity or mass

Gravity

On the physical density of grade three
At present, a 100ml water sample is collected from a certain reach of the Yellow River, and the measured mass is 101.8g. What is the sediment concentration of the Yellow River? (that is, how many kilograms of sediment are contained in 1 cubic meter of water) (the known sediment density is 2.5 times 10 to the third power kilogram per cubic meter)

Let the sediment concentration of the Yellow River be X
V water + V sand = 100cm ^ 3
ρ water V water + ρ sand V sand = 101.8g
So:
V water + V sand = 100cm ^ 3
V water + 2.5V sand = 101.8g
The solution is as follows
V sand = 1.2cm ^ 3
M sand = 2.5 × 1.2 = 3G
3/100=x/1000000
x=30000g=30kg