In a bizarre but harmless accident, a watermelon fell from the top of the eiffel tower. how fast was the watermelon traveling when it hit the ground 7.80 seconds after falling?

Gravity increases the speed of a falling object by 9.8 m/s for
every second that it falls.  If the object fell from rest (zero m/s),
then after 7.8 seconds, its speed was

             (7.8 sec) x (9.8 m/s²)  =  76.44 m/s  .

Explanation:

The capacitance of the capacitor is given by:

where

is the charge stored on the plates

V = 6.0 V is the potential difference across the capacitor

Substituting, we find

The capacitance of a parallel-plate capacitor is also given by

where

k = 6.4 is the dielectric constant

is the vacuum permittivity

is the area of each plate

d is the separation between the plates

Solving for d, we find