AP Physics C Questions on Momentum and Radiation Pressure

📚 Quick Study Guide

• 📐 Momentum (p): Defined as the product of mass (m) and velocity (v): $p = mv$. It's a vector quantity.
• 💥 Impulse (J): Change in momentum. Mathematically, $J = \Delta p = F\Delta t$, where F is the force and $\Delta t$ is the time interval.
• 🔒 Conservation of Momentum: In a closed system, the total momentum remains constant: $\Sigma p_{initial} = \Sigma p_{final}$.
• 🤝 Collisions:
  • Elastic: Kinetic energy is conserved.
  • Inelastic: Kinetic energy is not conserved.
  • Perfectly Inelastic: Objects stick together after the collision.
• ☀️ Radiation Pressure (P): The pressure exerted by electromagnetic radiation on a surface.
  • For complete absorption: $P = \frac{I}{c}$, where I is the intensity and c is the speed of light.
  • For complete reflection: $P = \frac{2I}{c}$.
• 💡 Intensity (I): Power per unit area: $I = \frac{P}{A}$.

🧪 Practice Quiz

1. Question 1: A 2 kg object is moving with a velocity of 5 m/s. What is its momentum?
   1. A) 2.5 kg m/s
   2. B) 7 kg m/s
   3. C) 10 kg m/s
   4. D) 20 kg m/s
2. Question 2: A ball with a mass of 0.5 kg strikes a wall with a velocity of 10 m/s and bounces back with a velocity of -8 m/s. What is the magnitude of the impulse on the ball?
   1. A) 1 kg m/s
   2. B) 5 kg m/s
   3. C) 9 kg m/s
   4. D) 18 kg m/s
3. Question 3: Two objects collide. Object A (3 kg) is moving at 8 m/s and object B (5 kg) is at rest. After the collision, the objects stick together. What is their final velocity?
   1. A) 0 m/s
   2. B) 3 m/s
   3. C) 5 m/s
   4. D) 8 m/s
4. Question 4: A photon with an intensity of 1500 W/m² is completely absorbed by a surface. What is the radiation pressure on the surface? (c = 3 x 10⁸ m/s)
   1. A) 5 x 10⁻⁶ N/m²
   2. B) 2.5 x 10⁻⁶ N/m²
   3. C) 7.5 x 10⁻⁶ N/m²
   4. D) 10 x 10⁻⁶ N/m²
5. Question 5: A 5 kg object moving at 6 m/s collides elastically with a 2 kg object at rest. What is the velocity of the 5 kg object after the collision?
   1. A) 1.71 m/s
   2. B) 3.43 m/s
   3. C) 6 m/s
   4. D) 8.57 m/s
6. Question 6: If the radiation pressure on a perfectly reflecting surface is 8 x 10⁻⁶ N/m², what is the intensity of the radiation? (c = 3 x 10⁸ m/s)
   1. A) 1200 W/m²
   2. B) 2400 W/m²
   3. C) 600 W/m²
   4. D) 4800 W/m²
7. Question 7: A system consists of two objects. Object A has a mass of 4 kg and a velocity of 3 m/s. Object B has a mass of 2 kg and a velocity of -6 m/s. What is the total momentum of the system?
   1. A) 0 kg m/s
   2. B) 6 kg m/s
   3. C) 12 kg m/s
   4. D) 24 kg m/s