Answer:4
Explanation:
Given
Frequency of beats is 3 beats per second
Frequency of first tuning fork is 
Beat frequency is difference in the frequency of tuning forks i.e.
either
or 
so 
or

so there is not enough information given to decide.
It’s C because just trust
Answer:

Explanation:
First, we are going to calculate the electrical potential in the point middle between the two charges
Remember that the electrical potential can be calculated as:

Where 
and it is satisfy the superposition principle, thus


The electrical potential at 10 cm from charge 1 is:


Since the work - energy theorem, we have:

where q is the electron's charge and m is the electron's mass
Therefore:

