I):final velocity=initial velocity+acceleration due to gravity*time of travel
Therefore,
v=0+9.8*3.1
=30.38 m/s
If by floor you meant water bed then i think there isn't enough info in the question.
Answer:
Part a)

Part b)

Part c)

Part d)

Part e)

Explanation:
Part a)
initial vertical position = 1.02 m
maximum height = 1.80 m





time taken by it to reach this height



Now when it again touch the ground then its speed is given as



time taken by it to reach this height





Part b)
Horizontal velocity



Part c)
vertical velocity is the intial y direction velocity

Part d)
Take off angle is given as


Part e)
initial vertical position = 1.20 m
maximum height = 2.50 m





time taken by it to reach this height



Now when it again touch the ground then its speed is given as



time taken by it to reach this height





Answer:
The capacitance per unit length is 
(b) is correct option.
Explanation:
Given that,
Radius a= 2.50 mm
Radius b=7.50 mm
Dielectric constant = 3.68
Potential difference = 120 V
We need to calculate charge per length for the capacitance
Using formula of charge per length

Put the value into the formula


We know that,

We need to calculate the capacitance per unit length
Using formula of capacitance per unit length



Hence, The capacitance per unit length is 