Final answer:
To have the same momentum as the concrete truck with a mass of 42,000 kg traveling at 18 m/s, a small car with a mass of 900 kg must travel at a speed of 840 m/s.
Step-by-step explanation:
The question being asked requires an understanding of the principle of conservation of momentum which states that the total momentum of a closed system is constant if no external forces are acting on it. The concrete truck has a mass of 42,000 kg and is traveling at a speed of 18 m/s. To find the momentum of the concrete truck, we use the formula:
p = m × v
Where p equals momentum, m equals mass, and v equals velocity. Therefore, the momentum of the concrete truck is:
p = 42000 kg × 18 m/s = 756000 kg·m/s
For the small car to have the same momentum, its velocity must be such that when multiplied by its mass, it equals the momentum of the concrete truck, so:
p = m × v
v = p / m = 756000 kg·m/s / 900 kg = 840 m/s
Therefore, the small car must travel at a speed of 840 m/s to have the same momentum as the concrete truck.