Real world examples of impulse and momentum

📚 Quick Study Guide

• ⚖️ Momentum: The product of an object's mass and velocity. It's a measure of how hard it is to stop a moving object. 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 to the object multiplied by the time the force is applied. Formula: $J = F\Delta t = \Delta p$, where $J$ is impulse, $F$ is force, $\Delta t$ is the change in time, and $\Delta p$ is the change in momentum.
• ➡️ Impulse-Momentum Theorem: States that the impulse acting on an object is equal to the change in momentum of that object. $F\Delta t = mv_f - mv_i$, where $v_f$ is the final velocity and $v_i$ is the initial velocity.
• 🏀 Real-world connection: Think about catching a ball. You apply an impulse to change the ball's momentum, bringing it to rest. The harder the ball is thrown (higher velocity), or the heavier it is (higher mass) the more impulse you need to stop it.
• 🚗 Another Example: Airbags in cars increase the time over which the force acts on a passenger during a collision, reducing the force and minimizing injury. They are designed to increase $\Delta t$ thereby decreasing $F$.

🧪 Practice Quiz

1. A baseball with a mass of 0.15 kg is moving at 40 m/s. What is the baseball's momentum?
   1. 0.6 kg m/s
   2. 6 kg m/s
   3. 60 kg m/s
   4. 600 kg m/s
2. A force of 10 N is applied to a box for 3 seconds. What is the impulse on the box?
   1. 3.33 Ns
   2. 10 Ns
   3. 30 Ns
   4. 13 Ns
3. A 2 kg ball moving at 5 m/s hits a wall and bounces back at 3 m/s. What is the change in momentum of the ball?
   1. 2 kg m/s
   2. 4 kg m/s
   3. 8 kg m/s
   4. 16 kg m/s
4. Which of the following scenarios involves the greatest impulse?
   1. A small force applied over a long time.
   2. A large force applied over a short time.
   3. A small force applied over a short time.
   4. A large force applied over a long time.
5. In a car crash, an airbag increases the time of impact. How does this affect the force experienced by the passengers?
   1. Increases the force.
   2. Decreases the force.
   3. Does not affect the force.
   4. Doubles the force.
6. A rocket expels gas to accelerate forward. Which principle best explains this phenomenon?
   1. Conservation of energy
   2. Conservation of mass
   3. Conservation of momentum
   4. Conservation of impulse
7. A bowling ball (mass = 7 kg) is traveling at 5 m/s towards a stationary pin (mass = 1.5 kg). After the collision, the pin moves at 6 m/s. What is the approximate new velocity of the bowling ball?
   1. 2.7 m/s
   2. 3.7 m/s
   3. 4.7 m/s
   4. 5.7 m/s