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Anonymous users2024-02-06Hello, I see your question.
Fourth, there are many professional forums and knowledge platforms on the Internet, and there are also a lot of information on them, and I always go to the forum to seek solutions to professional problems.
Fifth, ask your questions more carefully and clearly! It's easier for people to understand what it means!
Thanks for taking my suggestion! !
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Anonymous users2024-02-05Categorically discuss whether this direction, which is at an angle of 30° to the horizon, is oblique upwards or diagonally downwards.
Diagonally upward. Blocks receive an upward component of gravity, ground elasticity, and thrust in the vertical direction.
n=g-fsin30°=300n
Then the sliding friction force f= n=
The thrust is a pulling force in the horizontal direction is FCOS30°=346N F, so at this time, the block slides, and the friction force is 235N
When diagonally downward. Same as .
n=g+fsin30°=700n
Then the sliding friction force f= n=
The thrust is a tensile force in the horizontal direction, which is FCOS30°=346N, so at this time, the wooden block slides, and the friction force is 329N
In summary, the friction experienced by the wooden box is 329N
But if this question is larger, for example, it is necessary to pay attention to whether the wooden box smile can not be pushed, that is, the friction force is the static friction force, and the size is the horizontal component of the thrust.
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Anonymous users2024-02-04Because I'm typing on my phone, I can't type formula symbols, so I use words to express and ask.
Because the friction force is equal to the holding force of Zhihuiqing multiplied by the kinetic friction factor, and the support force is equal to the gravity of 500 N minus the thrust of 400 N multiplied by 60 more than 60 Niu, and the stuffy stool is 300 Niu.
So the friction is 300 times more.
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Anonymous users2024-02-03The speed of light is 3x10 to the 8th power of a meter second = 3x10 to the 5th power of a second.
The distance from the Earth to Mars is about 6x10 to the 7th power, and a total of 12x10 to the 7th power
12x10 to the 7th power km 3x10 to the 5th power km = 400 seconds.
So the lag is 400 seconds.
400x5=2000cm=20m
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Anonymous users2024-02-02Velocity formula for uniform linear motion:
Find velocity: v=s t
Find the distance: s=vt
2. The speed formula of variable speed linear motion: v=s t
3. The relationship between the weight and mass of an object: g=mg (g=4, the definition of density.
Find the density of a substance: =m v
Find the mass of the substance: m = v
Find the volume of the substance: v=m
4. Calculation of pressure.
Definition: p=f s (the substance can be applied in any state) liquid pressure: p= gh (h is the depth).
Find the pressure: f=ps
Find the force area: s=f p
5. Calculation of buoyancy.
Weighing method: f float = g—f
Formula method: f float = g row = v row g
Floatation method: F float = g object (v row v object).
Suspension method: F float = g matter (V row = V matter).
6. Leverage balance condition: f1l1=f2l2
7. Definition of work: w=fs
8. Power definition: p=w t
For the case of uniform linear motion: p=fv (f is the power) 9, mechanical efficiency: =w useful w total.
For lifting objects:
w useful = gh (h is the height).
W total = FS10, bevel formula: FL = gh
11. Endothermic and exothermic conditions when the temperature of the object changes.
Q aspiration = cmδt (δt = t-t0).
Q amp = cmδt (δt = t0-t).
12. Calculation of the heat emitted by fuel combustion: q discharge = qm
13. Thermal equilibrium equation: q suction = q discharge.
14. Heat engine efficiency: =w useful q discharge (q discharge=qm) 15, current definition: i=q t (q is the amount of electricity, the unit is coulomb) 16, ohm's law: i = u r
Deformation voltage: U=IR
Deformation resistance: r=u i
17. The characteristics of the series circuit: (taking the series connection of two pure resistive electrical appliances as an example) the relationship between voltage: U=U1+U2
Relationship of current: i=i1=i2
Relation of resistance: r=r1+r2
18. Characteristics of parallel circuits: (taking the parallel connection of two pure resistive electrical appliances as an example) the relationship between voltage: u=u1=u2
Relationship of current: i=i1=i2
The relationship of resistance: 1 r = 1 r1 + 1 r2
19. Calculation of electric work: w=uit
20. The definition of electric power: p=w t
Common formula: p=ui
21. Joule's law: q amp = i2rt
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