coulomb's law
f repulsive = q1q2/4 pi epsilon nought r squared
0.1= q1q2/4 pi epsilon nought 0.911 squared
q1+q2= 7.50 µC
0.1= q1(7.5µC-q1)/4 pi epsilon nought 0.911 squared
solve for q1
The release of free energy drives the spontaneous reaction.
Spontaneity can be <span>determined
using the change in </span>Gibbs free energy
(the thermodynamic potencial):
delta G=delta H – T*delta
S
where delta H is the enthalpy and delta S is the entropy.
The direction (the sign) of delta G depends of the changes
of enthalpy and entropy. If delta G is negative then the process is
spontaneous.
In our case, both delta H and delta S are negative values, the
process as said is spontaneous which means that it may proceed in the forward
direction.
Let's cut through the weeds and the trash
and get down to the real situation:
A stone is tossed straight up at 5.89 m/s .
Ignore air resistance.
Gravity slows down the speed of any rising object by 9.8 m/s every second.
So the stone (aka Billy-Bob-Joe) continues to rise for
(5.89 m/s / 9.8 m/s²) = 0.6 seconds.
At that timer, he has run out of upward gas. He is at the top
of his rise, he stops rising, and begins to fall.
His average speed on the way up is (1/2) (5.89 + 0) = 2.945 m/s .
Moving for 0.6 seconds at an average speed of 2.945 m/s,
he topped out at
(2.945 m/s) (0.6 s) = 1.767 meters above the trampoline.
With no other forces other than gravity acting on him, it takes him
the same time to come down from the peak as it took to rise to it.
(0.6 sec up) + (0.6 sec down) = 1.2 seconds until he hits rubber again.
Drop "moves" from the list for a moment.
You can also drop "stops moving", because that's included in "changes speed"
(from something to zero).
When an object changes speed or changes direction, that's called "acceleration".
I dropped the first one from the list, because an object can be moving,
and as long as it's speed is constant and it's moving in a straight line,
there's no acceleration.
I think you meant to say "starts moving". That's a change of speed (from zero
to something), so it's also acceleration.
