A 200 kg motorcycle speeds at 90 mph (40 m/s) off of a highway overpass and lands on top of a 18,000 kg semi truck, which is traveling in the same direction at 65 mph (30 m/s). Assume both vehicles stick together are coasting without friction after the collision. What will be the final speed of the semi truck after the collision

The final speed of the semi truck is 30.11 m/s.

Explanation:

Given;

mass of the motorcycle, m₁ = 200 kg

initial speed of the motorcycle, u₁ = 40 m/s

mass of the semi truck , m₂ = 18,000 kg

initial speed of the semi truck, u₂ = 30 m/s (same direction as u₁)

If the two vehicles stick together after collision, the final speed of the motorcycle will be equal to final speed of the semi truck = v

Apply the principle of conservation of linear momentum;

m₁u₁ + m₂u₂ = v(m₁ + m₂)

(200 x 40) + (18,000 x 30) = v(200 + 18,000)

8000 + 540,000 = v(18,200)

548,000 = v(18,200)

Therefore, the final speed of the semi truck is 30.11 m/s.

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