Examples of momentum and impulse in car crashes

📚 Quick Study Guide

• 🚗 Momentum: A measure of an object's mass in motion. Formula: $p = mv$, where $p$ is momentum, $m$ is mass, and $v$ is velocity.
• 💥 Impulse: The change in momentum of an object. It's equal to the force applied over a period of time. Formula: $J = F\Delta t$, where $J$ is impulse, $F$ is force, and $\Delta t$ is the change in time.
• 🤝 Impulse-Momentum Theorem: States that the impulse acting on an object is equal to the change in momentum of that object: $F\Delta t = \Delta p = m(v_f - v_i)$, where $v_f$ is the final velocity and $v_i$ is the initial velocity.
• ⚖️ Conservation of Momentum: In a closed system (like a car crash), the total momentum before the collision equals the total momentum after the collision.
• 📉 Effect of Crumple Zones: Crumple zones in cars increase the time of impact ($\Delta t$), which reduces the force ($F$) experienced by the occupants, as impulse ($J$) remains the same for a given change in momentum.

🤔 Practice Quiz

1. What is the formula for calculating momentum?
   1. A. $F = ma$
   2. B. $p = mv$
   3. C. $E = mc^2$
   4. D. $v = d/t$
2. Impulse is equal to:
   1. A. Change in velocity
   2. B. Applied force
   3. C. Change in momentum
   4. D. Initial momentum
3. A car crashes into a wall. What effect do crumple zones have on the force experienced by the occupants?
   1. A. Increase the force
   2. B. Decrease the force
   3. C. Have no effect on the force
   4. D. Double the force
4. If two cars collide and stick together, what remains constant in the system?
   1. A. Kinetic energy
   2. B. Velocity
   3. C. Momentum
   4. D. Force
5. A 2000 kg car is moving at 20 m/s. What is its momentum?
   1. A. 100 kg m/s
   2. B. 40,000 kg m/s
   3. C. 20 kg m/s
   4. D. 400 kg m/s
6. According to the impulse-momentum theorem, what is the relationship between impulse and change in momentum?
   1. A. Impulse is less than change in momentum
   2. B. Impulse is greater than change in momentum
   3. C. Impulse is equal to change in momentum
   4. D. Impulse is inversely proportional to change in momentum
7. A force of 1000 N is applied to a car for 0.5 seconds during a crash. What is the impulse?
   1. A. 500 Ns
   2. B. 2000 Ns
   3. C. 1500 Ns
   4. D. 1000 Ns