Static friction and dynamic friction When the thrust is greater than the maximum static friction, the object is pushed, Then the force can be reduced slightly Doesn't the thrust have to be less than the maximum static friction? If it's less than, it's still This becomes: thrust is greater than the maximum static friction, impossible. Thrust is less than the maximum static friction, static. Then how does it move

Static friction and dynamic friction When the thrust is greater than the maximum static friction, the object is pushed, Then the force can be reduced slightly Doesn't the thrust have to be less than the maximum static friction? If it's less than, it's still This becomes: thrust is greater than the maximum static friction, impossible. Thrust is less than the maximum static friction, static. Then how does it move

First, use the thrust force greater than the maximum static friction force to make the object move,
As long as the object moves, let the thrust be less than the maximum static friction

What does static friction have to do with dynamic friction?

0 ＜ static friction ＜ = maximum static friction, which must be solved by force analysis
For example, if the pushing box is not pushed, the static friction will be as large as the thrust
The sliding friction is related to friction coefficient and positive pressure, f = UFN, FN is positive pressure,

What do the sliding friction formula F = μ n mean?
If you know, say it!

Sliding friction: the force that occurs between two objects that contact each other and slide relative to each other and prevents them from sliding relative to each other. The direction of friction is opposite to the direction of relative motion or the direction of relative motion trend of the object, rather than the direction of motion of the object. Friction can be used as power or resistance

The two lamps are marked with "220 V & nbsp; 60 W" and "220 V & nbsp; 15 W" respectively______ The consumption of electric power is large

∵ P = u2r, the rated voltage of a and B lamps are the same, p a ＞ P B, ∵ r a ＜ R B, ∵ they are connected in series in a 220 V circuit, ∵ according to the formula P = I2R, the actual power can be calculated, the current is the same, the greater the resistance, the greater the actual power, that is, the actual power of B lamp is greater

Four rational numbers a, B, C, D satisfy | ABCD | / ABCD = 1, find the value of | a | / A + | B | / B + | / C + | / D | / d

When all four are positive, |a | / A + | B | / B + | C | / C + | / D | / D = 4
When 2 is positive and 2 is negative, | a | / A + | B | / B + | / C + | / D | / D = 0
When all four are negative, |a | / A + | B | / B + | C | / C + | / D | / D = - 4

In the circuit shown in the figure, if the slide of sliding rheostat is moved, the indication of voltmeter changes from 6V to 5V, and the indication of ammeter changes by 0.2A, then the change of power consumed by the constant value resistor is ()
A. 0.2WB. 1.0WC. 1.2WD. 2.2W

According to the circuit diagram, the resistance R is connected in series with the sliding rheostat, the voltmeter measures the voltage at both ends of R, and the ammeter measures the current in the circuit; when the indication U1 of the voltmeter is 6V, the current I1 = u1r = 6vr -------- (1) when the indication U2 of the voltmeter is 5V, the current I2 = u2r = 5vr -------- (2) from the title, it can be known that i1-i2 = 0.2A -------- (3) from (1) to (2) it can be obtained that r = 5 Ω, I1 = 6vr = 6v5 Ω = 1 2a, I2 = 5vr = 5v5, Ω = 1a. According to P = UI, the change of power consumed by the constant resistance △ P = P1-P2 = u1i1-u2i2 = 6V × 1.2a-5v × 1A = 2.2W

Party A, Party B and Party C produce a batch of toys. Party A produces 1 / 2 of the sum of Party B and Party C, Party B produces 1 / 3 of the sum of Party A and Party C, and Party C produces 2400 toys. How many toys are there in total?

A produces 1 / 2 of the sum of B and C, and a produces 1 / (1 + 2) = 1 / 3 of the total
B produces 1 / 3 of the sum of a and C, and B produces 1 / (1 / 3) = 1 / 4 of the total
C produced 1-1 / 3-1 / 4 of the total = 5 / 12
This batch of toys has a total of 2400 △ 5 / 12 = 5760 pieces

How to measure the electric power of household appliances with energy meter?
How to measure the electric power of household appliances with electric energy meter?
Within three minutes, urgent, thank you!

P = w / T W unit kwh t unit hour P unit kw
W = lap speed per revolution / lap speed per kilowatt hour consumed per revolution

Given X / y = 2, find the value of 2x (x + y) - Y (x + y) / 4x & # 178; - 4xy + Y & # 178

X / y = 2, so x = 2Y
2x(x+y)-y(x+y)/4x²-4xy+y²
｛2（2y）（2y+y）-y（y+2y）｝/{4*4y^2-4(2y)y+y^2}
={12y^2-3y^2}/{16y^2-8y^2+y^2}={9y^2}/{9y^2}=1
If you don't understand,

What is the atomic weight of an element?

Absolutely right answer:
Atomic weight: the ratio of the mass of an atom of an element divided by 1 / 12 of the mass of C-12
This definition already gives the calculation method of atomic weight