If the plane from which the bottle was dropped was flying at an altitude of 500m and the bottle lands 400m horizontally from
the initial dropping point, how fast was the plane flying when the bottle was
released?

Friction is the force that act and opposes all motion of moving objects

    m₁v₁ + m₂v₂ = (m₁ + m₂)vmomentum is conserved.the left-hand side of the equation represents the momentum in the system before the collision.the right-hand side represents the momentum in the system after the collisionm₁ and v₁ represents the mass and the velocity of the physics blockm₂ and v₂ represents the mass and velocity of the ball of puttyv represents the final velocity of the combined mass.the question states the two masses stick together. they combined mass has its own velocity with the body mass the sum of the two objects' massestheir combined momentum is (m₁ + m₂)vto find the magitude of (m₁ + m₂)v, we need to add the vectors on the left-hand side of the equation: m₁v₁ + m₂v₂.note the diagram. i have positioned the vectors in accordance with their directions.the magnitude of the resultant can be calculated using the pythagorean theorem since this is a right triangle situation (north and west are perpendicular)|(m₁ + m₂)v| =  √[ (m₁v₁)² + (m₂v₂)² ]|(m₁ + m₂)v| =  √[ (1.5kg·8.0m/s)² + (0.40kg·20m/s)² ]|(m₁ + m₂)v| =  14.4 kg m/sfor two significant figures (assuming that 20m/s is two), this rounds to 14 kg m/s

Average net force: ∑f = fapp + fgrav = 8.20 + (-9.81m/s²)(0.500 kg)           = 3.295 n          = 3.30 nvelocity of object∑f = maa = ∑f / m = 3.295 n / 0.500 kg = 6.59 m/s²v² = v₀² + 2adv = √(v₀² + 2ad)v = √[ 0² + 2(6.59m/s²)(1.50m) ]v = 4.45 m/s