Answer:
electrons
Explanation:
The total charge Q is the sum of the charge of the N electrons contained in the sphere:

charge of a electron
We solve to find N:

Answer:
649kg/m^3
Explanation:
Let p be the density of this particular object.
Formula for density:

We can substitute the givenmass and volume to find density of the object.

Therefore the density of this object is 649kg/m^3.
Answer:
t = 2.2 s
Explanation:
Given that,
A person observes a firework display for A safe distance of 0.750 km.
d = 750 m
The speed of sound in air, v = 340 m/s
We need to find the between the person see and hear a firework explosion. let it is t. So, using the formula of speed.

So, the required time is 2.2 seconds.
Answer:
The answer to your question is letter B.
Explanation:
To answer this question, we must remember the third law of motion of Newton that states that For every action, there is an equal and opposite reaction.
Then, if the action force is 40 N to the right, the reaction force must be 40 N to the left.
<span>Both electric and magnetic fields exert body forces, meaning they act from a distance. The like charges and poles in both repel; positive charge repels positive and the north pole repels the north pole. For both, the opposite poles/charges attract. Finally, only magnetic fields have poles, and there are two poles, namely the south and north, so they are dipolar.
The diagram that represents all of this information correctly is the third.</span>