Physics 2 Calculation Questions, 20

1) Q suction

2) Q gold c suck, then C 900

1) Find the amount of heat absorbed by the iron pot? q1＝

2) Find the amount of heat absorbed by water? q2＝

3) Seeking the quality of water? m＝

Solution:1(1) Q suction = C water m water t

4200j/（kg,°c）*（30g/1000g）kg*（30°c-25°c）

4200j*

630J2)C Metal = Q Discharge (M Metal * T)630J (10G 1000G)KG * (100°C-30°C) 630J

630j/°c）

2.(1) How much heat does it take to heat iron from 15°C to 90°C without heat loss?

Solution: q suction=c iron m iron t

15°c)17250j

A: Excluding heat loss, it takes 17250J to heat iron from 15°C to 90°C.

2) How much heat is lost in the process?

Solution: q loss = q release - q suction = 962250j-17250j = 945000j =

A: Heat is lost in the process.

3) How many degrees can the temperature of the water rise if the heat lost in this process is used to heat 10kg of water?

Solution: t=q loss c water m water.

Answer: The heat lost in this process is used to heat 10kg of water, and the temperature of the water can rise thanks to o( o

Pressure limiting valve gravity g=mg=

The cross-sectional area of the outlet hole s= r = d 4 = m = the pressure generated by the pressure limiting valve p = g s =, this is the maximum pressure difference, and the force that can be withstood at least at the interface of a standard atmospheric pressure cooker cover is.

f=ps pot=

The maximum pressure difference between the inside and outside of the pressure cooker is the pressure caused by the pressure limiting valve. p=g/s=

How many standard atmospheres p = standard atmospheric pressure = standard atmospheric pressure.

At least how much force can a pressure cooker lid withstand? f=ps=

First calculate the length of the Earth's equator, that is, the circumference with a radius of 6400km, 6400km=, c=2, so the length of the oxygen molecule l=, the number of revolutions=

If the object is moving at a constant velocity, then the force of the object in the direction of motion is stationary.

There are only two forces in the direction of motion of an object: tension and friction.

Explanation: These two forces are equal in magnitude and opposite in direction.

If the tensile force is 10N, the friction force is also 10N.

In addition, it is easy to understand that if the object moves forward 1m, the rope must also be pulled 1m!

Because the acceleration of uniform motion a=0, the tensile force is equal to the drag force and the ground friction force is equal to f(10n).

The distance the rope moves is equal to the distance the object travels, both of which are 1m

The pulling force acting on the object is 20 N, because the object moves in a straight line at a uniform speed, so the tensile force and the friction force are a pair of balanced forces, so the friction force is 20 N. Draw a force analysis diagram.

Because s=vt=multiplied by 10s=1m

No diagram, no way. The conjecture is that it is a flat pulley group, but it is unknown that it is composed of several fixed pulleys and movable pulleys, and the number of rope strands cannot be judged. You can only do it by filling in the picture.

I don't understand what it means, there is a picture, there is no picture.

The pulling force is 20n; The friction is 20n; The distance is 1m

The charge carried by the glass rod is positive.

Number of charges: =2 10 10

Solution: Silk sassafras glass rod, silk is negatively charged, glass rod is positively charged.

The charge carried by the glass rod is positive, and according to the conservation of charge, the charge charge can be known as.

Happy New Year!

The glass rod rubs against the silk to make the glass rod carry a charge to the power of -9, and the charge carried by the glass rod is a positive charge, and the charge with it = 1e=

The charge carried by the glass rod is positive, and the amount of charge carried by 10 electrons to the 18th power is 1 coulomb.

I have to say that you cured me of cervical spondylosis for many years...

25.Set the fulcrum to be 2-x meters away from the left end, and the power according to the lever balance condition Power arm = resistance The resistance arm can establish the equation 100n x meters = 60n (2-x) meters.

Solution x = m.

Note that it is to be converted into SI units) = to the sixth power of ten.

2.According to the equilibrium of the two forces, group f = f movement.

From w=fs deformation, s=w f (I won't write the process, the phone is not good to play) = 1500m

1.Let the mass of the aluminum be m kilograms.

m cubic = m + cubic m = use the density formula, and then you can do the math yourself.

2 270g-220g = 50g v=m p = 50g 1g per cubic centimeter = 50 cubic centimeters.

420g-270g = 150g p = m v = 150g 50 cubic centimeters = 3 10 cubic kilograms per cubic meter.

I'm just like you, we're also learning about density, let's shake hands. Study hard, some can't see anything, you just make equations, and the equal amount is equal to the same amount.

1.Since only the mass changes but the volume does not change, let the volume v and the mass of iron must be greater than the mass of aluminum according to m=pv, so the cubic of * v + the cubic of v gives v=2000 cubic meters.

2.Because the volume of the cup can be calculated by filling it with water, knowing the density of water, 270g cubic centimeters, and the total mass is 420g, the mass of the gold nugget is 420g-270g=150g, and the volume of exposed water can be calculated as 150g cubic centimeters, which is the volume of the iron block, so p=mv=150g, 150 cubic centimeters=cubic centimeters.

1.(Iron Dense Aluminum Dense) v=

v. Watertight except 50

m 420-220=200

Matter density m matter except v matter.

1. M iron - m aluminum =

Iron 00kg m3 v aluminium = v iron and v aluminium are equal.

2. V gold = (270g-220g) density of 1000kg m3 metal block = (420g-220g) v gold.

v=5*10^-4

According to the title, the overflow water is 270g-220g=50g, and its volume is 50g (1g cm 3)=50cm 3, which is the volume of the alloy block.

In addition, the mass of the alloy block is 420g-220g=200g, so the density is 200g 50cm 3=4g cm 3=4*10 3kg m 3