If I'm not mistaken the answer would be c, vibrations and wave phenomena, because when sound waves hit your ear they go through it to your brain and your mind translates these vibrations to sound. I hope my answer helped you out.
Not sure the precise concept of "normal observation", but I assume that is observed by "eyes".
Eye observation is basically macroscopic, but when you use a mark, which can be regarded as a point of mass, then it goes to microscopic.
Mark is a reference point which you can compare the relative position change, but with your eyes, first you cannot notice microscopic changes, second the eyes cannot precisely set a stable reference point.
Answer:
the final potential energy of this system is 3U0/10
Explanation:
We are given
charge at left end and another test charge at point p
Potential energy is given by = 
where k is electrostatics constant = 
Q1 = first charge , Q2= test charge
R= distance between charges
potential at point p
U0 = k*Q1*Q2 /3 ⇒ kq1q2 = 3U0 ..............1
now the test charge moves to point R
using Pytahgoreou theorem
R(distance) = 
= 10
New Potential energy
U1 = kq1*q2 / 10
substituting kq1q2 = 3U0 from 1
U1 = 3U0/10
So this is the final potential energy of this system.
When they say use energy, you want to use
Total energy = potential energy + kinetic energy = mgh + 1/2mv²
I assume you mean 200 g ball,
so, we know the total distance traveled is going to be 13 - 1.3 = 11.7 m
If the ball just makes it to the top ( 13 m ) , then the ball will stop moving and the kinetic energy will be 0,
therefore, the potential energy at the top will be the total energy of the system = mgh
from this, we say that mgh = 1/2mv² solve for v
<span>
v = sqrt (2gh) = 15.2 m/s </span>
Answer:
applying 1st eq of motion vf=vi+at we have to find a=vf-vi/t here a=50-30/2=10 so we got a=10m/s²
