<u>The answer is not contained detail explanation, just a solution and the required values. </u>
All the details are in the pictures, the answers are marked with orange colour.
Note,
in the task no 20.:

V - the velocity of the pair of the balls after collision.
in the task no 21:
m₁ - the mass of the copper ball; m₂ - the mass of the copper calorimeter; m₃ - the mass of the water; t₀ - the initial temperature of water in the copper calorimeter; θ - the final temperature in the calorimeter after the copper ball is transferred into a copper calorimeter; t₁ - the required initial temperature of the copper ball before it is transferred into the calorimeter.
Answer:
The magnitude of the net electric field is:

Explanation:
The electric field due to q1 is a vertical positive vector toward q1 (we will call it E1).
On the other hand, the electric field due to q2 is a horizontal positive vector toward q2(We will call it E2).
Knowing this, the <u>magnitude of the net electric</u> field will be the<u> E1 + E2. </u>
Let's find first E1 and E2.
The electric field equation is given by:

Where:
- k is the Coulomb constant (k = 9*10^{9} Nm²/C²)
- q1 is the first charge
- d1 is the distance from q1 to P


And E2 will be:



Finally, we need to use the Pythagoras theorem to find the magnitude of the net electric field.



I hope it helps you!
Answer:
8.60 g/cm³
Explanation:
In the lattice structure of iron, there are two atoms per unit cell. So:
where
an and A is the atomic mass of iron.
Therefore:

This implies that:

= 
Assuming that there is no phase change gives:

= 8.60 g/m³
Answer:
681.6/ms
Explanation:
A reconnaissance plane flies 545 km away from its base at 568 m/s. then flies back to its base at 852 m/s.
What is its average speed?
Answer in its of m/s
Avg speed of the round trip is
2*568*852/(568+852)= 681.6/ms
I belive what your looking for is oxygen