There are two physics experiment questions that come to the master

1. First measure the mass m1 of the metal particles with a balance, and then measure the mass m2 of the beaker filled with water to add the masses of the two. The metal particles are then placed in a beaker (some of the water will be spilled), and the volume of the spilled water is the volume of the metal.

Then measure the mass m3 of the beaker filled with metal particles, then the density of the metal is:

m1/(m1+m2-m3)

2. First measure the length l and width b of the gold foil with a millimeter scale, calculate the area l*b, and then measure the mass m of the gold foil with a balance, because the density is known to be m, the thickness of the gold foil is m (*l*b).

1.Density is volume and mass, and mass can be directly weighed by a balance. Here's how to solve the volume.

Put the metal particles in the beaker, the volume of the spilled water can be solved by the quality of the spilled water, how to deal with the quality of the water.

The mass of water and metal minus the mass of metal is the mass of the remaining water, and the total mass minus the mass of the remaining water is the mass of the overflow water, which of course includes the beaker. The mass of the spilled water divided by the density of the water is the volume, which is the volume of the metal.

Finally, dividing the mass by the volume is the density.

First weigh the mass m1 of the filled beaker and water, then put the metal particles into the beaker and weigh the mass m2, take out the mass m3 of the beaker and water, and calculate the volume of the missing water v. according to the scale on the beaker

p=m/v=(m2-m3)/v

1. Measure the mass of metal particles m1, 2. Measure the mass of a beaker filled with water m2, 3. Put the metal particles into a beaker filled with water, and measure the overall mass m3, 4 m1 multiplied by the density of water divided by [m1+m2-m3].

1) ACE density = m1 (V3-V1).

Method (1) Balance to measure the quality of the scale to measure the length of the edge can be calculated with the density formula.

2) Balance to measure the mass, put very fine white sugar in the graduated cylinder, use white sugar instead of water to calculate the volume of the sugar cube on the side, and use the density formula to calculate it.

3) Balance to measure the quality: Put excess white sugar into the graduated cylinder to make a saturated solution of sugar, pour it into the graduated cylinder, and then put the sugar cube into the graduated cylinder and enter the pants for buried measurement.

The density of the liquid is equal to the product of the depth of the surface below, and the pressure of the liquid on the lower surface of the cylinder is equal.

The greater the product of the density of the liquid and the depth of the lower surface, the greater the pressure of the liquid on the lower surface of the cylinder.

The pressure difference between the upper and lower surfaces of a cylinder immersed in the same liquid is equal to that of the liquid, regardless of its depth.

The greater the density of the liquid, the greater the pressure difference between the upper and lower surfaces of the cylinder.

1) Experimental circuit diagram.

2) Experimental Procedure:

According to the circuit diagram, six bright shooting resistors R1, R2, R3, R4, R5 and R6 with different resistance values and a voltmeter are connected to the circuit.

Close the switches, measure the voltage at both ends of R1, and record the resistance value and voltage indication number of R1.

Disconnect the switch and connect the voltmeter to both ends of R2. Close the switches, measure the voltage at both ends of R2, and record the resistance value of R2 and the number of leakage voltages.

According to the steps, the voltages at the resistors R3, R4, R5 and R6 are measured respectively, and the resistance values of R3, R4, R5 and R6 and the corresponding voltage representations are recorded.

When r1 tends to increase to its maximum, the voltage in the line is the electromotive force of the power supply.

The voltage at both ends of the voltmeter or at the end is , and the internal resistance of the voltmeter and the resistance r2 are equal, so the voltage at both ends of the resistance r2 is also .

Therefore, the electromotive force of the power supply is.

When r1=0.

The voltage at both ends of the voltmeter is , and the internal resistance of the voltmeter and the resistance R2 are equal, so the voltage at both ends of the resistance R2 is also .

The line refers to the only positive voltage in the group regret.

EMF u = u outside + u inside =

So ir=20

The internal resistance of the power supply is 20

This can happen on an alluvial plain, where your well is drilled 100m and may not hit the bedrock, and the pumping is shallow pore water.