<span>In order for the results to be valid, the dependent variable can only be affected by the independent variable, so somethings need to be kept constant. The things that need to be kept constant are called controlled variables.</span>
Answer:
Either heat added or mechanical work done.
Explanation:
Since he found stirring rod on the desk and a cigarette lighter. This means that the beaker was probably either heated with the aid of fire from the lighter.
Also, the stirring rod could have been used to stir the water which will increase the kinetic energy which also means an increase in temperature.
Thus, it's either heat was added or mechanical work was done as a result of stirring.
Answer:
Explanation:
Force between charge is given by the following expression
F = k Q₁ Q₂ / R² , k = 9 x 10⁹ , Q₁ and Q₂ are charges , R is distance between charges .
Putting the given values ,
.85 = 9 x 10⁹ x 7.1 x 10⁻⁶ x Q₂ / 5.4²
Q₂ = .85 x 5.4² / (9 x 10⁹ x 7.1 x 10⁻⁶ )
= .38788 x 10⁻³ C .
= 387.88 x 10⁻⁶ C .
Protons and neutrons are packed together in a very small region called nucleus. Protons are positively charged and we know that like charges repel. Then how is it that protons are not repelling each other and flying away from nucleus?
You may think that gravitational force is holding all the protons together but it is not so. Gravitational force is many times weaker than repulsive force.
It is actually strong force which holds proton together. At this short distance, strong force comes into play and is several times stronger than the repulsive force.
