Physics momentum question?
2019-02-20 12:57 am
A 8,000.0 kg railroad car traveling at 10.00 m/s strikes a second boxcar at rest. The two stick and move together at 3.00 m/s. What is the mass of the second car?
回答 (2)
2019-02-20 1:44 am
Total momentum before collision = Total momentum after collision
m₁u₁ + m₂u₂ = (m₁ + m₂) v
8000.0 × 10.00 + m₂ × 0 = (8000.0 + m₂) × 3.00
80000 = 24000 + 3.00m₂
3.00m₂ = 56000
Mass of the second car, m₂ = 18700 kg
m₁u₁ + m₂u₂ = (m₁ + m₂) v
8000.0 × 10.00 + m₂ × 0 = (8000.0 + m₂) × 3.00
80000 = 24000 + 3.00m₂
3.00m₂ = 56000
Mass of the second car, m₂ = 18700 kg
2019-02-20 3:40 am
During a collision, momentum is conserved.
Initial momentum = 8,000 * 10 = 80,000 kg * m/s
Let m be the mass of the second car.
Final momentum = (8,000 + m) * 3 = 24,000 + 3 * m
24,000 + 3 * m = 80,000
3 * m = 56,000
m = 56,000 ÷ 3 = 18,666⅔ kg
Check:
Total mass = 8,000 + 18,666⅔ = 26,666⅔ kg
Final momentum = 26,666⅔ * 3 = 80,000 kg * m/s
This proves that the mass of the second railroad car is correct. I hope this is helpful for you.
Initial momentum = 8,000 * 10 = 80,000 kg * m/s
Let m be the mass of the second car.
Final momentum = (8,000 + m) * 3 = 24,000 + 3 * m
24,000 + 3 * m = 80,000
3 * m = 56,000
m = 56,000 ÷ 3 = 18,666⅔ kg
Check:
Total mass = 8,000 + 18,666⅔ = 26,666⅔ kg
Final momentum = 26,666⅔ * 3 = 80,000 kg * m/s
This proves that the mass of the second railroad car is correct. I hope this is helpful for you.
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