Ok this is probably the easiest part in physics so lol dont panic. now the way you round is by looking at the exponent which in this case for the first one is -9 so 6.8 is gonna be 0000000068. because when you have a negative exponent you move the decimal to the west side. when you have a positive decimal you move to the east side. I will not do the second one because its best if you try to solve it so you can learn it. good luck my friend.
The term that describes the number of thoughs that pass a point in a given amount of time is FREQUENCY.
In wave theory, frequency refers to the number of wave that pass through a fixed point in a given amount of time. Frequency is usually measure in Hertz. The mathematical formula for finding frequency is:
F = Velocity of wave / wavelength of wave.
The answer of this question is D. All of the above
Acceleration happen when an obeject change its velocity. It has nothing to do with speed.
The huge misconception about acceleration is when we thought it only aply if we increase our speed ( in a sport match, sportcaster often describe acceleration as an increase in players speed)
slower, faster, right , left, it does not matter, as long as that object change its velocity, it accelerates
(a) 
According to Newton's second law, the force experienced by each balloon is given by:
F = ma
where
m = 0.021 kg is the mass
a = 1.1 m/s^2 is the acceleration
Substituting, we found:
The electrostatic force between the two balloons can be also written as
where
k is the Coulomb's constant
Q is the charge on each balloon
r = 16 m is their separation
Since we know the value of F, we can find Q, the magnitude of the charge on each balloon:
(b) 
electrons
The magnitude of the charge of one electron is
While the magnitude of the charge on one balloon is
This charge can be written as
where N is the number of electrons that are responsible for this charge. Solving for N, we find:
