Physics buoyancy calculation As shown in the figure, when a weight of 4kg is put on the block, the upper surface of the block is just level with the water surface. If a 5kg object is hung under the block, the upper surface of the block is also just level with the water surface. The density of the object is calculated Let's omit the picture

Physics buoyancy calculation As shown in the figure, when a weight of 4kg is put on the block, the upper surface of the block is just level with the water surface. If a 5kg object is hung under the block, the upper surface of the block is also just level with the water surface. The density of the object is calculated Let's omit the picture

Let m 1 be the mass of the weight, M 2 be the mass of the object, v be the volume of the object, G be the gravity of the wood block, v be the volume of the wood block, then for the first time, M 1 G + G wood = ρ water V wood g, and for the second time, M 2 G + G wood = ρ water V wood G + ρ water V wood G

Calculate buoyancy
What is the buoyancy of a 79g iron block when it is put in water? (the density of the iron block is known to be 7.9 * 10 cubic kg / m3)

No bonus, f = PVG = 0.00001m ^ 3 * 1000kg / m ^ 3 * 10N / kg = 0.1N

Calculating formula of Physics
Just give me the formula of sound transmission. I have forgotten the English letters for distance and time. I'll give you a question with the general influence. You can make a formula for me with the English letters
A driver with a speed of 20km / h honked to a valley somewhere. 4S heard the echo and asked the distance between the honking place and the valley
It's very easy to do this problem. What I lack at present is to use English letters to express these quantities. This problem is in the learning guide of people's education press. It can be calculated by the propagation speed of sound in the air of 15 degrees

The speed of sound propagation has nothing to do with the speed of the speaker. Don't be confused by the speed of 20km / h. in 4 seconds, the vehicle moves forward. S = VT = 5.55 * 4 = 22.22m is the return journey of echo, which is 22.22m less. S = VT = 340 * 4 = 1360m plus 22.22m less, which is 1382.22m