Where to buy the first three physical units synchronous detection

= w has Pynai w total.

gh w always cautious and envious.

mgh w total.

Substituting data: wide mining.

90% = 18kg 10n kg total.

The total amount of work that needs to be done to lift the object: w total = 100j

First, the pressure of p= gh water on the bottom of the test tube:

p=ρgh=；

or p= gh=;

Second, from P=Fs to obtain F=Ps to find the upward pressure of water on the bottom of the test tube:

f=ps=980pax8x10 The writing here should be -4 power)!!

or f=ps=10 pax8x10 find the gravitational force of the iron block by "g iron = f-g pipe":

g iron = f-g tube =

or g iron = f-g tube =

The first question is directly set of formulas, and the second question A is subject to the same amount of buoyancy as the gravitational force of A and the iron, and then it is OK to use the buoyancy formula to bring in the calculation.

Depth in water l=h=10cm=

p= g h = 1000 Pa (g takes 10n kg) buoyancy = ps = 1000 g =

Bottom pressure p= gh Note that h is the height of submersion.

That is, the gravity of the 10cm test tube + the gravity of the iron = the force of water on the bottom of the test tube (f = p * s, s is the bottom area of the test tube).

I know how to count it exactly.

The volume of the water tower has been changed to 20 cubic meters, right?? w = gh = mgh = 20000 * 10 * 10 = 2000000J, mechanical efficiency and let the rot trace and 50%.' w'=4000000j '/p=4000000/1000=4000s

During the flight of the football in the air, because of gravity, the ball crosses a curve in the air, so the force is applied to the object Earth.

With elimination, the weightless environment of space cannot be carried out, while c, the spring tensioner stretches with elastic potential energy, to overcome this, the astronaut has to do work, so c

Dear, you're doing the right thing. The formula is pretty standard. It would be perfect if you added some necessary Chinese characters to the steps of the physics problem.