Power is the energy in a system per time. It will have units of Watts which is equal to joules per second. It can be expressed as:
P = E / t
where E = Force x distance
P = Fd / t
t = Fd / P
t = 8 (9.72) / 3.0
t = 25.92 s
Answer:

Explanation:
The capacitance of the parallel-plate capacitor is given by

where
ϵ0 = 8.85x10-12 C2/N.m2 is the vacuum permittivity
k = 3.00 is the dielectric constant
is the area of the plates
d = 9.00 mm = 0.009 m is the separation between the plates
Substituting,

Now we can calculate the energy of the capacitor, given by:

where
C is the capacitance
V = 15.0 V is the potential difference
Substituting,

Answer:
When the ball goes to first base it will be 4.23 m high.
Explanation:
Horizontal velocity = 30 cos17.3 = 28.64 m/s
Horizontal displacement = 40.5 m
Time
Time to reach the goal posts 40.5 m away = 1.41 seconds
Vertical velocity = 30 sin17.3 = 8.92 m/s
Time to reach the goal posts 40.5 m away = 1.41 seconds
Acceleration = -9.81m/s²
Substituting in s = ut + 0.5at²
s = 8.92 x 1.41 - 0.5 x 9.81 x 1.41²= 2.83 m
Height of throw = 1.4 m
Height traveled by ball = 2.83 m
Total height = 2.83 + 1.4 = 4.23 m
When the ball goes to first base it will be 4.23 m high.