As the plastic sphere is charged, therefore it experience an electric force when placed in an electric fields and also experiences gravitational force acts downward so the electric force must act upward.
Let 
is electric force and 
is gravitational force.
If these forces are balanced, therefore
or 
Given, 
and 
.
Substituting these values in above equation we get,
Thus, the magnitude of electric field is 
.
As the charge is negative, the electric field at the location of the plastic sphere must be pointing downward.
Answer:
this is an observation.
Explanation:
you are observing that the ball is partially white
Is there any possible chance that at some point in your science
studies, sometime before you were given this question for your
homework, that maybe you might have encountered this formula
for the period of a simple pendulum ?
Period = (2 pi) √(length/gravity) .
If the length is 0.23 meter, and the
acceleration of gravity is 9.8 m/s²,
then the period is
= (2 pi) √(0.23/9.8)
= 0.963... second (rounded)
That's how long it takes for a simple pendulum, 23cm long,
hanging on a massless string and not swinging too far to
the side, to complete one full swing left and right.
Now, if you can figure out how many periods of 0.963 second
there are in 30 seconds, you'll have your answer. I'll leave
that part of it to you.
Answer:
Total kinetic energy of entire system is 3 mgl
Explanation:
Given two masses: m and 4m.
Since the pulley is frictionless and the thread is massless, the energy here is linked to the two masses.
Total kinetic energy of entire system = decrease in gravitational potential energy of the system.
Therefore, we have :
ΔKE = Δp
ΔKE = 4mgl - mgl
= 3 mgl
Total kinetic energy of entire system is 3 mgl
Vernal equinox, for spring.
