Answer:
The horizontal velocity is 
Explanation:
From the question we are told that
The mass of the pumpkin is 
The distance of the the car from the building's base is 
The height of the roof is 
The height is mathematically represented as

Where g is the acceleration due to gravity which has a value of 
substituting values

making the time taken the subject of the formula


The speed at which the pumpkin move horizontally can be represented mathematically as

substituting values


Explanation:
Given that,
Mass of the car, m₁ = 1250 kg
Initial speed of the car, u₁ = 7.39 m/s
Mass of the truck, m₂ = 5380 kg
It is stationary, u₂ = 0
Final speed of the truck, v₂ = 2.3 m/s
Let v₁ is the final velocity of the car. Using the conservation of momentum as :



So, the final velocity of the car is 2.5 m/s but in opposite direction. Hence, this is the required solution.