Answer:
4.69 s
Explanation:
u = Initial velocity = 30 m/s
= Angle of launch = 
g = Acceleration due to gravity = 
Time taken by the projectile to land is given by
The time the projectile is in the air before it contacts the ground again is 4.69 s.
Answer: The potential energy of the weights is 24,500 J
Explanation:
For an object of mass M, that is at a distance H from the ground, the potential energy can be written as:
U = M*H*g
where g is the gravitational acceleration g = 9.8m/s^2
In this case, we have that:
mass of the weights = 1,250 kg
height = 2m
Then the potential energy of the weights is:
U = 2m*1,250kg*9.8m/s^2 = 24,500 J
(18 gallon/tank) x (23 mile/gallon) = <em>414 mile/tank</em>
